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ATST-Tools | ABACUS,ASE与过渡态理论的碰撞
ABACUS
ASE
TS
催化计算
ABACUSASETS催化计算
量子御坂
发布于 2024-01-03
推荐镜像 :atst-tools:1.3.1
推荐机型 :c2_m4_cpu
赞 9
8
1. 过渡态与过渡态搜索
1.1 简介
1.2 NEB方法与Dimer方法
1.2.1 NEB方法
1.2.2 AutoNEB方法
1.2.3 Dimer方法
2. ATST-Tools及其使用
2.1 ASE中的过渡态搜索
2.2 通过ATST-Tools进行过渡态搜索
2.3 通过ATST-Tools进行振动计算和自由能较正
3. 总结

【ATST-Tools】,全名【Advanced ASE Transition State Tools for ABACUS】, 是基于ASE调用ABACUS进行过渡态搜索计算的工作流脚本集,涵盖ASE中包含的NEB,AutoNEB和Dimer方法,并预期未来基于ASE以及ASE-ABACUS接口进一步接入或开发其他的过渡态搜索方法

在完成这个教程之后,你将能够:

  • 学习过渡态理论与过渡态搜索中的基础知识

  • 掌握在ATST-Tools工作流组织下,使用ASE调用ABACUS进行过渡态搜索计算的前处理,具体计算和后处理工作的方法

欢迎大家提出改进意见!

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©️ Copyright 2024 @ Authors
作者: 刘照清(James Misaka) *** 📨
日期:2024-01-03
共享协议:本作品采用知识共享署名-非商业性使用-相同方式共享 4.0 国际许可协议进行许可。
快速开始:点击上方的 开始连接 按钮,选择 atst-tools:1.3.1 镜像 和任意配置机型即可开始。 注:由于具体计算的案例都需要比较长的计算时间,本案例不会要求完成具体计算,只涉及预处理和结果分析,故使用c2_m4_cpu即可。如果你想进行具体计算,可使用c16_m32_cpu, c32_m64_cpu等具有较高核数的机型

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Open In Bohrium

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1. 过渡态与过渡态搜索

这部分的内容来自笔者的一些粗浅认知。一些参考资料如下:

  • 侯文华等译. Atkins' Physical Chemistry 第十一版中文版 Page. 772.
  • 单斌. 计算材料学. Page. 224
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1.1 简介

化学是一门研究物质组成,结构及其变化的学科,其主要的研究对象都是物质之间的相互反应,这些反应过程往往由一系列基元反应组成,而这一系列基元反应的发生都离不开反应的过渡态。

过渡态由过渡态理论引出,它认为:在A -> B的反应过程中,反应物A会经历一个能量较高的临界状态,并经此亚稳定态转化为产物B,这种临界状态即为过渡态。它是反应能垒的来源,并与反应速率直接相关。

reaction_diffusion

化学反应图示。黑线为能量曲线,「反应物, 生成物」对应极点,「过渡态」对应鞍点

在(基于BO近似的)势能面上,这种过渡态位置表现为马鞍点,其能量对坐标的一阶梯度为0,且二阶梯度仅在反应坐标方向为负,其他位置为正,并且也仅在反应坐标方向上存在一个虚频。反应经由这样一个**最小能量路径(Minimum Energy Path, MEP)**进行,从反应物经过渡态生成产物。

PES

势能面上的极小点(稳定结构),过渡态(马鞍点结构)与最小能量路径

基于统计热力学的方法可以推导得到Eyring过渡态理论,该理论指出,基元反应的活化自由能,即过渡态自由能与反应物自由能之差,可以直接与反应速率常数联系起来,即: 从而基元反应的反应速率可以通过反应物与过渡态的信息计算得到。

过渡态是一种典型的稀有事件,无论是扩散过程、解离过程、还是其他各种均相/多相的化学反应过程,其微观机制均涉及对过渡态的分析,从而过渡态的理论研究与实验检测都是化学研究的重要组成部分。同时,过渡态搜索则是通过理论模拟方法寻找过渡态的关键。过渡态搜索的方法有很多,其中最常用的是NEB和Dimer方法。当然,新的过渡态搜索方法也在不断涌现,尤其是近年来我们很惊喜地看到基于机器学习的生成扩散模型在过渡态搜索与反应生成方面起到了非常惊艳的效果(戳这里

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1.2 NEB方法与Dimer方法

NEB方法和Dimer方法代表着搜索过渡态的两类不同方法,其一是基于已知反应物和产物的信息去搜索过渡态,其二是已知过渡态的一个初始猜测去搜索过渡态。

1.2.1 NEB方法

NEB方法,即Nudge Elastic Band方法,是chain-of-states大类过渡态方法中最著名的一个,其基本原理为:

  1. 在初态(第0个态)和末态(第P个态)之间生成P-1个映像(images),这些映像的编号从1到P-1,每个映像代表势能面上连接初末态的一个点,它们同时出现在势能面连接初末态的反应路径上,并在彼此之间通过弹簧力耦合,组成一条映像链(chain)。
  2. 对整条链进行优化,使这条映像链拟合到MEP上,其能量最高点即为反应过渡态,而整条映像链则代表反应路径,
  3. 在整条链的优化过程中,第i个映像的受力并不是完整的势能梯度+弹簧力,而是二者的投影。如图所示:

alt

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在目前最为常用的IT-NEB(improved-tangent NEB)方法中,映像在链上的切线方向一般定义为指向能量更高的邻近映像的方向(当然了这个切线方向最终要归一化),即: 并在能量极值点做平均化处理,使各个点处的切线具有较好的连续性:

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与此同时,为了使NEB映像链能更好地定位过渡态,在进行了几步NEB迭代计算之后,将NEB链上能量最高点的映像的受力进行调整,使之不受弹簧力约束,但沿切线方向上的受力反向,即: 即是Climbing-Image NEB方法,简写为CI-NEB方法。这一受力调整不影响计算量,且能明显提升过渡态的解析度。在实际的过渡态搜索中,IT-NEB结合CI-NEB是最常用的方式,能较为高效地定位过渡态与反应路径

alt

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1.2.2 AutoNEB方法

IT-NEB+CI-NEB已经是非常好的NEB搜索方法了,诚然NEB方法存在一些细节上要注意的问题,比如初末态间原子需要匹配(这是个大难点),纯粹的线性插值容易使初始映像链的结构过于不合理(可以用IDPP插值方法解决)等,但这些都不是非常关键的问题。

一个较为关键的问题在于,NEB计算时映像链的数目都是从最初就确定不变的,虽然这使得每个映像的能量/受力可以单独计算从而明显提升并行度,但这种并行计算的过程中,越靠近过渡态的点其电子结构自洽收敛越困难,也即NEB映像链上各个映像并非同时计算结束,会导致计算资源分布不平衡。同时,传统NEB计算哪怕是采用IDPP等改进的插值方法生成初始NEB链,也会导致各个映像分布过于均衡,对过渡态位置缺乏解析度。

Hammer课题组提出的AutoNEB方法可以缓解上述问题,并明显提升NEB的效率,减小NEB的计算量。其算法示意图如下图所示:

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alt

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AutoNEB的核心是NEB链上的映像会在计算过程中动态地加入,其算法逻辑可以简述为

  1. 从初末态+少量初猜构成的NEB链出发,完成(较粗精度的)NEB计算。
  2. 定位该NEB链上几何结构/能量差别最为明显的两个映像,在这两个映像间通过插值方法加入一个新的映像
  3. 以该新的映像为中心,继续进行(较粗精度的)NEB计算(该过程中有些原有映像是不会参与计算的),得到一条新的连接初末态的NEB链。
  4. 重复上述两步,直至NEB链上映像个数达到设定阈值
  5. 以能量最高点为中心,最后进行一步(目标精度的)CI-NEB计算,得到最终的NEB链
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AutoNEB与传统NEB的对比可从下图看出:

alt

通过AutoNEB这样的动态NEB过程,新加入的映像将对过渡态和反应路径有更好的解析度,并且显著缓解NEB的计算资源不平衡问题,以及NEB的计算量。

这两种方法都内置在了ASE中,并可在ATST-Tools中方便地使用

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1.2.3 Dimer方法

(基本原理晚点再写)

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2. ATST-Tools及其使用

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此前,我们介绍过ASE-ABACUS接口的一些基础使用(回顾点这个)。本期我们补上过渡态搜索的坑。同时,本教程还会涉及基于ASE进行过渡态计算信息收集,针对过渡态和反应初末态的振动校正等操作。

2.1 ASE中的过渡态搜索

ASE中有三种过渡态搜索方法

  1. 约束优化法,在一维反应坐标上进行约束与爬升,放开其他自由度优化,逐步逼近过渡态。这一方法简单且直觉性强,但难以处理复杂过渡态。该方法可以通过ase.optimize.climbfixinternals.BFGSClimbFixIntgernals模块调用
  2. NEB方法及其变体,可通过ase.mep.neb调用。其中,AutoNEB方法需要通过ase.mep.autoneb调用
  3. Dimer方法,可通过ase.mep.dimer调用
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2.2 通过ATST-Tools进行过渡态搜索

在熟练了ASE和ASE-ABACUS接口的代码逻辑之后,直接写一个python脚本,调用ABACUS等计算组件,基于ASE进行过渡态搜索计算,并不是一件非常困难的事情。但我们或许有更好的办法。

在ATST-Tools中,与过渡态搜索相关的前处理,具体计算与后处理工作被合理模块化与耦合起来,我们只需要进行简单的编辑设置,就可以在服务器等命令行环境下快速开展过渡态搜索工作。

ATST-Tools可以通过如下链接访问: https://github.com/QuantumMisaka/ATST-Tools 。其README中有详细的环境配置和使用方法介绍。

在本notebook的推荐镜像中已经装有ATST-Tools及其依赖环境。我们可以进入相关目录查看

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[1]
cd /opt/ATST-Tools
/opt/ATST-Tools
/usr/local/lib/python3.10/dist-packages/IPython/core/magics/osm.py:417: UserWarning: using dhist requires you to install the `pickleshare` library.
  self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
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[2]
ls
README.md  dimer/  examples/  img/  neb/  relax/  source/  vibration/
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在ATST-Tools的母目录中我们可以看到这些件夹:

  • dimer:使用ATST-Tools进行Dimer计算所需的脚本。
  • neb:使用ATST-Tools进行NEB计算时所需的脚本。
  • vibration:进行振动计算和自由能校正时所需的程序,此处使用ASE进行振动计算。
  • relax:使用ASE-ABACUS进行结构优化计算的脚本。
  • source:ATST-Tools整合的Python库,包括用ase-abacus接口进行NEB, Dimer等运算时的工作流配置,以及自行微调/添加的过渡态计算方法等。
  • examples: ATST-Tools进行计算的案例。这些案例可以在已经配好的服务器/Bohrium镜像下经微调直接运行。

在实际使用ATST-Tools之前,我们需要让Python能识别到source目录下的Python库,通过:

export PYTHONPATH=/opt/ATST-Tools/source:$PYTHONPATH

完成这个过程,你的镜像应当已经配置好了。

在README中有对ATST-Tools非常详细的介绍,我们可以看一看。这个README非常的长,我们设置为了滚动模式。

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cat README.md
# ATST-Tools
Advanced ASE Transition State Tools for ABACUS, including:
- NEB, including CI-NEB, IT-NEB and others
- AutoNEB: an automatic NEB workflow
- Dimer
- Vibration analysis

Version v1.3.1

Copyright @ QuantumMisaka from PKU & AISI

## Dependencies:
- [ASE](https://wiki.fysik.dtu.dk/ase/about.html)
- [ABACUS](https://abacus.deepmodeling.com/en/latest/)
- [ASE-ABACUS interface](https://gitlab.com/1041176461/ase-abacus)
- [GPAW](https://wiki.fysik.dtu.dk/gpaw/install.html) if one wants to run NEB images relaxation in parallel

Notice: GPAW and ABACUS should be dependent on same MPI and libraries environments. 
For instance, if your ABACUS is installed by Intel-OneAPI toolchain, your GPAW should NOT be dependent on gcc-toolchain like OpenMPI and OpenBLAS.

ATST-Tools is Under actively development, please let me know if any problem occurs.

## Workflow

![ATST-workflow](./img/ATST-workflow.png)

## Workflow libraries and setting
All workflow library files and re-constructed ASE libraries will be put in `./source` directory. including:
```bash
source
├── abacus_autoneb.py
├── abacus_dimer.py
├── abacus_neb.py
└── my_autoneb.py
```
Before use running scripts, you should add these libraries into your PYTHONPATH:
```bash
export PYTHONPATH=/path/to/source:$PYTHONPATH
```

## Developing
- [x] Use interface to read ABACUS STRU file and ABACUS output
- [x] Flexible input for different NEB method in ASE
- [x] `DyNEB` implementation and test
- [x] Now used optimum option: idpp-guess + IT-NEB + CI-NEB parallel method
- [x] Give an initial guess print-out of NEB images
- [x] Decoupling to init-guess -> NEB calculation -> result post-process
- [x] Parallel computing during images relaxation by `gpaw python`
- [x] `AutoNEB` implementation
- [x] Give user a way to specify constraint information (along one direction) and initial magnetic moments (for each atom of one element) for NEB initlal guess chain and two end points (while these information cannot be read from calculation result)
- [x] More test in surface reaction system
- [x] Connected to Dimer method
- [x] More test in magnetic surface reaction system
- [x] Put calculation setting in an independent file (decoupling *_run.py)
- [x] Vibration analysis scripts 
- [x] More easily and proper way to do continuation calculation for NEB and AutoNEB. (next target)
- [ ] More fiexible options for NEB, Dimer and AutoNEB, like full properties in trajectory file, and fiexibly utilize SCF wavefunction/charge output files from previous calculation.


## NEB workflow

### Method
- For serial NEB calculation, DyNEB, namely dynamic NEB method `ase.mep.neb.DyNEB` is for default used.
- For parallel NEB calculation, `ase.mep.neb.NEB` traditional method is for default used.
- The Improved Tangent NEB method `IT-NEB` and Climbing Image NEB method `CI-NEB` in ASE are also default used in this workflow, which is highly recommended by Sobervea. In `AutoNEB`, `eb` method is used for default, but Improved Tangent method is also recommended.
- Users can change lots of parameter for different NEB setting. one can refer to [ASE NEB calculator](https://wiki.fysik.dtu.dk/ase/ase/neb.html#module-ase.neb) for more details: 
- The workflow also support use `AutoNEB` method in ASE。You can view AutoNEB method in paper below. Also. One can refer to [AutoNEB](https://wiki.fysik.dtu.dk/ase/ase/neb.html#autoneb) to view it. 
> E. L. Kolsbjerg, M. N. Groves, and B. Hammer, J. Chem. Phys, 145, 094107, 2016. (doi: 10.1063/1.4961868)

The AutoNEB method in ASE lies in `ase.mep.autoneb.AutoNEB` object, which will do NEB calculation in following steps:
1. Define a set of images and name them sequentially. Must at least have a relaxed starting and ending image. User can supply intermediate guesses which do not need to have previously determined energies (probably from another
NEB calculation with a lower level of theory)
1. AutoNEB will first evaluate the user provided intermediate images
2. AutoNEB will then add additional images dynamically until n_max is reached
3. A climbing image will attempt to locate the saddle point
4. All the images between the highest point and the starting point are further relaxed to smooth the path
5. All the images between the highest point and the ending point are further relaxed to smooth the path

Step 4 and 5-6 are optional steps. Note that one can specify different `fmax` for CI-NEB in step 4 compared with other NEB calculation, which can be set as `fmax=[fmax1, fmax2]` in `AutoNEB` object.

> Notice: in surface calculation and hexangonal system, the vaccum and c-axis should be set along y-direction but not z-direction, which is much more efficient for ABACUS calculation.


### Usage
#### Basic NEB
The NEB workflow is based on 3 main python scripts and 1 workflow submit script. Namely:

- `neb_make.py` will make initial guess for NEB calculation, which is based on ABACUS (and other calculator) output files of initial and final state. This script will generate `init_neb_chain.traj` for neb calculation. Also, You can do continuation calculation by using this script. You can get more usage by `python neb_make.py`. 
- `neb_run.py` is the key running script of NEB, which will run NEB calculation based on `init_neb_chain.traj` generated by `neb_make.py`. This script will generate `neb.traj` for neb calculation. Users should edit this file to set parameters for NEB calculation. sereal running can be performed by `python neb_run.py`, while parallel running can be performed by `mpirun gpaw python neb_run.py`.
When running, the NEB trajectory will be output to `neb.traj`, and NEB images calculation will be doing in `NEB-rank{i}` directory for each rank which do calculation of each image. 
- `neb_post.py` will post-process the NEB calculation result, which will based on `neb.traj` from neb calculation. This script will generate nebplots.pdf to view neb calculation result, and also print out the energy barrier and reaction energy. You can get more usage by `python neb_post.py`. Meanwhile, users can also view result by `ase -T gui neb.traj` or `ase -T gui neb.traj@-{n_images}:` by using ASE-GUI
- `neb_submit.sh` will do all NEB process in one workflow scripts and running NEB calculation in parallel. Users should edit this file to set parameters for NEB calculation. Also this submit script can be used as a template for job submission in HPC. the Default setting is for `slurm` job submission system.

#### AutoNEB method 
In ATST-Tools, the AutoNEB method can be easily used by the following scripts
- `autoneb_run.py` is the key running script for `AutoNEB` method, which is like `neb_run.py` but the NEB workflow in `AutoNEB` is enhanced and the I/O logic have some difference. Users can use it with `mpirun gpaw python autoneb_run.py` by existing `init_neb_chain.traj` which can only contain initial and final state or contain some initial-guess.
- `autoneb_submit.sh` will do all AutoNEB process in one workflow and running AutoNEB calculation in parallel. Users should edit this file to set parameters for AutoNEB calculation. Also this submit script can be used as a template for job submission in HPC. the Default setting is for `slurm` job submission system.
- `neb_make.py` and `neb_post.py` can be used for `AutoNEB` method, but the workflow have slight difference. 

#### Running
Users can run NEB each step respectively: 
1. `python neb_make.py [INIT/result] [FINAL/result] [n_max]` to create initial guess of neb chain
   1. Also You can use `python neb_make.py -i [input_traj_file] [n_max]` to create initial guess from existing traj file, which can be used for continuation calculation.
2. `python neb_run.py` or `mpirun -np [nprocs] gpaw python neb_run.py` to run NEB calculation
3. `python neb_post.py neb.traj [n_max]` to post-process NEB calculation result

Users can run AutoNEB each step respectively:
1. `python neb_make.py [INIT/result] [FINAL/result] [nprocs]` to create initial guess of neb chain
2. `mpirun -np [nprocs] gpaw python autoneb_run.py` to run AutoNEB calculation
3. `python neb_post.py --autoneb run_autoneb???.traj` to post-process NEB calculation result

Also, user can run each step in one script `neb_submit.sh` by `bash neb_submit.sh` or `sbatch neb_submit.sh`. AutoNEB scripts usage is like that. 

> Notice: Before you start neb calculation process, make sure that you have check the nodes and cpus setting and other setting like n_max, constraints and initial magnetic moments in `*neb_submit.sh` and `*neb_run.py` to make sure that you can reach the highest performance and reach the simulation result you want !!!   

#### Visualize
You can simply use ASE-GUI to have a view of NEB or AutoNEB trajectory.

For NEB, you can view all running trajectory by 
```bash
ase -T gui neb.traj 
```
You can also view the last 10 images by
```bash
ase -T gui neb.traj@-10:
```
For AutoNEB, the most recent NEB path can always be monitored by:
```bash
ase -T gui -n -1 run_autoneb???.traj
```

#### Continuation calculation for NEB
If NEB or AutoNEB is break down somehow, you can do continuation calculation based on saved trajectory files and ATST-Tools scripts.

For NEB, you can simply:
```bash
python neb_make.py -i neb.traj [n_max] [fix and mag information]
```
to generate `init_neb_chain.traj` for continuation calculation. You can also `python neb_post.py neb.traj` to generate the latest neb band `neb_latest.traj` and do continuation calculation by `python neb_make.py -i neb_latest.traj [n_max]`. note that `n_max = n_image - 2`

For AutoNEB, you need to get `neb_latest.traj` in a more compicated way, especially for the first NEB step in AutoNEB running:
```bash
python traj_collect.py ./AutoNEB_iter/run_autoneb???iter[index].traj
```
to generate `collection.traj` from certain index (like 006) stage of AutoNEB calculation. Another way to do the same thing is:
```bash
python traj_collect.py ./run_autoneb???.traj
```
or
```bash
python traj_collect.py ./AutoNEB_iter/run_autoneb???iter00[i].traj
```
or
```bash
python traj_collect.py ./AutoNEBrun_rank?/STRU
```
When `collection.traj` is gotten, one can do
```bash
python neb_make.py -i collection.traj [n_max] [fix and mag information]
```
to generate `init_neb_chain.traj` for continuation calculation.

If one want to continue calculation with the interrupted autoneb, one can:
```bash
python traj_collect.py --no-calc ./run_autoneb???.traj 
```
and `--no-calc` noted can be anywhere.

> Note: Linux shell will automatically detect and sort number of index, so you will not be worried about using format like `run_autoneb???iter005.traj`, the consequence will be right, for example:
```bash
 test> ll run_autone*.traj
-rw-r--r-- 1 james james 6.0K Nov 24 20:35 run_autoneb000.traj
-rw-r--r-- 1 james james 6.4K Nov 24 20:35 run_autoneb001.traj
-rw-r--r-- 1 james james 6.4K Nov 24 20:35 run_autoneb002.traj
-rw-r--r-- 1 james james 531K Nov 24 20:35 run_autoneb003.traj
-rw-r--r-- 1 james james 531K Nov 24 20:35 run_autoneb004.traj
-rw-r--r-- 1 james james 531K Nov 24 20:35 run_autoneb005.traj
-rw-r--r-- 1 james james 531K Nov 24 20:35 run_autoneb006.traj
-rw-r--r-- 1 james james 6.4K Nov 24 20:35 run_autoneb007.traj
-rw-r--r-- 1 james james 6.4K Nov 24 20:35 run_autoneb008.traj
-rw-r--r-- 1 james james 6.5K Nov 24 20:35 run_autoneb009.traj
-rw-r--r-- 1 james james 6.5K Nov 24 20:35 run_autoneb010.traj
-rw-r--r-- 1 james james 6.5K Nov 24 20:35 run_autoneb011.traj
-rw-r--r-- 1 james james 6.5K Nov 24 20:35 run_autoneb012.traj
-rw-r--r-- 1 james james 531K Nov 24 20:37 run_autoneb025.traj
```


#### Other scripts
Because ATST is originally based on ASE, the trajectory file can be directly read, view and analysis by `ase gui` and other ASE tools. Abide by `neb_make.py` and `neb_post.py`, We also offer some scripts to help you:
- `neb_dist.py`: This script will give distance between initial and final state, which is good for you to check whether the atoms in two image is correspondent, and is also a reference for setting number of n_max
- `traj_transform.py`: This script can transfer traj files into other format like `extxyz`, `abacus`(STRU), `cif` and so on (coming soon). Also if user specify `--neb` option, this script will automatically detect and cut the NEB trajectory when doing format transform. This script will be helpful for analysis and visualization of NEB trajectory.
- `traj_collect.py`: This script can collect structure files into a trajectory file, which is specifically used for NEB continuation calculation.


## Dimer workflow

### Method
(Waiting for update)


### Usage
The Dimer workflow is based on 2 main python scripts and 2 workflow submit script. Namely:
- `neb2dimer.py` can be used by `python neb2dimer [neb.traj] ([n_max])`, which will transform NEB trajetory `neb.traj` or NEB result trajectory `neb_result.traj` to Dimer input files,  including:
- - `dimer_init.traj` for initial state of Dimer calculation, which is the highest energy image, namely, TS state. 
- - `displacement_vector.npy` for displacement vector of Dimer calculation, which will be generated from position minus of the nearest image before and after TS point, and be normalized to 0.01 Angstrom. 
- `dimer_run.py` is the key running script of Dimer calculation, which will run Dimer calculation based on `dimer_init.traj` and `displacement_vector.npy` generated by `neb2dimer.py` or based on other setting. This script will generate `dimer.traj` for Dimer calculation trajectory. Users should edit this file to set parameters for Dimer calculation, and run Dimer calculation by `python dimer_run.py`. When running, any Dimer images calculation will be doing in `Dimer` directory.
- `dimer_submit.sh` will do Dimer workflow in one scripts. The Default setting is for `slurm` job submission system.

> Notice: this dimer method will have some problem in running process.


## Vibration Analysis 
The vibration analysis is based on `ase.vibrations.Vibrations` object, which can be used by `python vib_analysis.py` to do vibration analysis by finite displacement method for initial, final and transition state. The result will be printed out  and saved in `running_vib.out` file. All force matrix for displaced and normal mode will also be saved and printed.

Also, thermodynamic analysis will be performed based on `ase.thermochemistry.HarmonicThermo` object based on vibration analysis result and specified temperature.

## Relaxation
Relaxation method offer by ASE can be used by scripts from `relax` directory, which use ABACUS as SCF calculator. 


## Notices
### Property Loss in Trajectory 
Some property should be get via specific way from trajectory files, and some will be lost in trajetory files, 
- Stress property will not be stored in trajetory file
- In NEB calculation, the Force property for fixed atoms and Stress property will NOT be stored in trajectroy file, which is still in work
- in Dimer calculation, the Energy, Forces and Stress property will be stored in trajetory file after specified which properties need to be stored.
- in AutoNEB calculation, all property in processing trajectory will be stored in AutoNEB_iter directory, but in the result `run_autoneb???.traj`, the forces and stress information will be lost.


## Examples
- Li-diffu-Si: Li diffusion in Si, very easy example for serial and parallel NEB calculation
- H2-Au111: H2 dissociation on Au(111) surface. which will have NEB, AutoNEB and Dimer example. The barrier is around 1.1 eV consistent with existing paper and calculation result.
- N2-Cu111 : N2 dissociation on Cu(111) surface. which have high barrier as 4.0 eV but it's not hard to calculate
- CO-Pt111 : CO dissociation on Pt(111) surface. which have high barrier as 3.6 eV and including diffusion part. AutoNEB will always fail due to the low starting image. 
- Cy-Pt_graphene: Cyclohexane dehydrogenation on Pt-doped graphene surface. The barrier is around 1.3 eV. Noted that the `IT-NEB` result is wrong, but which is consistent to the result in VTST-Tools when using 4 image to do IT-NEB calculation.
- C-C coupling on Fe5C2(510) surface: C-C coupling on Fe5C2(510) surface with CO co-adsorption, which have 0.48 eV barrier in calculation result and existing paper. This is a typical example for reaction on magnetic surfaces.

More examples is welcomed from users. 
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examples文件夹中提供了几个简单的例子的输入与输出。这些例子在具体使用ATST-Tools并调用ABACUS进行计算时会耗费较长的运算时间。一般来说,在16个物理核上,Li-diffu-Si的NEB例子会花费1-2小时左右的时间,H2-Au111以及Cy-Pt@graphene会耗费12-24小时左右的时间,感兴趣的小伙伴可以自行拉取ATST-Tools源码并运行

git clone https://github.com/QuantumMisaka/ATST-Tools

这里我们直接看看

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cd /opt/ATST-Tools/examples/
/opt/ATST-Tools/examples
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[6]
ls
 C-C-Fe5C2_510/  'Cy-Pt@graphene'/   H2-Au111/   Li-diffu-Si/   N2-Cu111/
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我们先看一个简单的例子,Li-diffu-Si跑的是Li在硅晶胞中的扩散。进入到文件夹中,其中有两个算例文件夹dyneb, neb和数据文件夹datadyneb是ASE中实现了的一种针对串行NEB进行了优化的NEB算法,neb中则是传统的并行NEB方法。由于该过程仅设计Li原子的扩散,因而在初末态之间插入3个映像,即可很好地得到扩散过渡态结构与扩散路径。

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[7]
cd /opt/ATST-Tools/examples/Li-diffu-Si
/opt/ATST-Tools/examples/Li-diffu-Si
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[8]
ls
data/  dyneb/  neb/
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这个例子如果采用3个映像插值,在c32_m64_cpu机器来运行,并采用串行优化的NEB方法,可以在1-2个小时内运行完毕。具体设置方法如下。

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mkdir dyneb-example
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[10]
cp -r data/* dyneb-example
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cd dyneb-example
/opt/ATST-Tools/examples/Li-diffu-Si/dyneb-example
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通过上述方法准备好数据文件,包括:

  • 初末态的计算结果
  • 计算所用的赝势和轨道文件

之后,通过ATST-Tools中的neb_make.py脚本进行插值,在Bohrium上我们需要通过python3来调用python。这一脚本的使用方法可以通过直接运行查看。不难发现,该脚本支持在加入初猜的时候显式地加入基底约束,磁矩初猜,过渡态初猜等信息,并允许加载已有的初猜NEB链,灵活性非常强。

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! python3 /opt/ATST-Tools/neb/neb_make.py
Usage: 
Default: 
    python neb_make.py [init_image] [final_image] [n_max] [optional]
[optional]:
    --fix [height]:[direction] : fix atom below height (fractional) in direction (0,1,2 for x,y,z), default None
    --mag [element1]:[magmom1],[element2]:[magmom2],... : set initial magmom for atoms of element, default None
    --format [format]: input image-files format, support abacus-out, vasp-out, extxyz, traj and others which have calculated property information, default None for automatically detect
    --ts [ts_guess]: use TS guess to make image chain, default None
Use existing guess and do continuation calculation
    python neb_make.py -i [init_guess_traj] [n_max] [optional]
Notice: n_max is related to the number of interpolated image, not include initial and final image

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! python3 /opt/ATST-Tools/neb/neb_make.py ./INIT/OUT.ABACUS/running_scf.log ./FINAL/OUT.ABACUS/running_scf.log 3
----- Get NEB guess chain only by initial and final state -----
--- Successfully make guessed image chain by idpp method ! ---
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通过上述方法我们能得到init_neb_chain.traj。这一二进制轨迹格式是ASE官方指定的轨迹存储格式,并能直接被ATST-Tools利用。

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[16]
ls
FINAL/               Li_gga_8au_100Ry_4s1p.orb    init_neb_chain.traj
INIT/                Si_ONCV_PBE-1.2.upf
Li_ONCV_PBE-1.2.upf  Si_gga_8au_100Ry_2s2p1d.orb
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于是我们完成了NEB的插值过程,接下来可以利用ATST-Tools开展NEB计算。这里分别展示串行DyNEB计算和并行NEB计算的过程,这些计算默认并不直接进行。

一般来说,在准备好初猜之后,将ATST-Tools/neb目录中的neb_run.py拷贝到目录下,微调其设置,然后即可运行该脚本来跑NEB计算。

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cp /opt/ATST-Tools/neb/neb_run.py .
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[20]
cat neb_run.py
# JamesMisaka in 2023-11-27
# Run NEB calculation on NEB images by ASE-ABACUS
# part of ATST-Tools scripts

from ase.optimize import FIRE, BFGS
from ase.io import read, write
from abacus_neb import AbacusNEB

# setting
mpi = 8
omp = 4
fmax = 0.05  # eV / Ang
neb_optimizer = FIRE # suited for CI-NEB
neb_directory = "NEBrun"
algorism = "improvedtangent" # IT-NEB is recommended
climb = True
dyneb = False  
parallel = True
k = 0.10 # eV/Ang^2, spring constant
init_chain = "init_neb_chain.traj"
abacus = "abacus"
#lib_dir = "/lustre/home/2201110432/example/abacus"
lib_dir = ""
pseudo_dir = f"{lib_dir}"
basis_dir = f"{lib_dir}"
pp = {
      'C':'C_ONCV_PBE-1.0.upf',
      'H':'H_ONCV_PBE-1.0.upf',
      'Pt':'Pt_ONCV_PBE-1.0.upf',
      }
basis = {
         'C': 'C_gga_7au_100Ry_2s2p1d.orb',
         'H': 'H_gga_6au_100Ry_2s1p.orb',
         'Pt': 'Pt_gga_7au_100Ry_4s2p2d1f.orb'
         ,}
kpts = [2, 1, 2]
parameters = {
    'calculation': 'scf',
    'nspin': 2,
    'xc': 'pbe',
    'ecutwfc': 100,
    'dft_functional': 'pbe',
    'ks_solver': 'genelpa',
    'symmetry': 0,
    'vdw_method': 'd3_bj',
    'smearing_method': 'gaussian',
    'smearing_sigma': 0.001,
    'basis_type': 'lcao',
    'mixing_type': 'broyden',
    'scf_thr': 1e-6,
    'scf_nmax': 100,
    'kpts': kpts,
    'pp': pp,
    'basis': basis,
    'pseudo_dir': pseudo_dir,
    'basis_dir': basis_dir,
    'init_wfc': 'atomic',
    'init_chg': 'atomic',
    'cal_force': 1,
    'cal_stress': 1,
    'out_stru': 1,
    'out_chg': 0,
    'out_mul': 0,
    'out_wfc_lcao': 0,
    'out_bandgap': 0,
    'efield_flag': 1,
    'dip_cor_flag': 1,
    'efield_dir': 1,
    'efield_pos_max': 0.0
}


if __name__ == "__main__":
# running process
# read initial guessed neb chain
    init_chain = read(init_chain, index=':')
    neb = AbacusNEB(init_chain, parameters=parameters, parallel=parallel,
                    directory=neb_directory, mpi=mpi, omp=omp, abacus=abacus, 
                    algorism=algorism, k=k, dyneb=dyneb)
    neb.run(optimizer=neb_optimizer, climb=climb, fmax=fmax)


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需要编辑的地方主要有;

  • 赝势与轨道文件所在目录pseudo_dir, basis_dir
  • 目标体系的赝势与轨道信息
  • INPUT参数设置和K设置
  • 其他关于NEB运行相关的设置。

如果直接在notebook中运行,默认跑的是串行版本的NEB计算,并行计算需要利用mpirun调用gpaw的python,需要在命令行进行。

以下是串行运行NEB的脚本,采用了Dynamic的串行优化方法。脚本第一行将脚本写入到dyneb_run.py文件中,并可在命令行调用。由于该程序不对NEB本身做并行,用户可以将该行去掉,并在c32_m64_cpu机器中直接运行该代码。

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%%writefile dyneb_run.py

# erase the row above and you can run it in notebook

from ase.optimize import FIRE, BFGS
from ase.io import read, write
from abacus_neb import AbacusNEB

# setting
mpi = 16
omp = 1
fmax = 0.05 # eV / Ang
neb_optimizer = FIRE # suited for CI-NEB
neb_directory = "NEBrun"
algorism = "improvedtangent" # IT-NEB is recommended
climb = True
dyneb = True
parallel = False
k = 0.10 # eV/Ang^2, spring constant
init_chain = "init_neb_chain.traj"
abacus = "abacus"
#lib_dir = "/lustre/home/2201110432/example/abacus"
lib_dir = ""
pseudo_dir = f"{lib_dir}"
basis_dir = f"{lib_dir}"
pp = {
'Li':'C_ONCV_PBE-1.2.upf',
'Si':'H_ONCV_PBE-1.2.upf',
}
basis = {
'Li': 'Li_gga_8au_100Ry_4s1p.orb',
'Si': 'Si_gga_8au_100Ry_2s2p1d.orb',
,}
kpts = [2, 2, 2]
parameters = {
'calculation': 'scf',
'nspin': 1,
'xc': 'pbe',
'ecutwfc': 100,
'dft_functional': 'pbe',
'ks_solver': 'genelpa',
'symmetry': 0,
'vdw_method': 'none',
'smearing_method': 'gaussian',
'smearing_sigma': 0.001,
'basis_type': 'lcao',
'mixing_type': 'broyden',
'scf_thr': 1e-6,
'scf_nmax': 100,
'kpts': kpts,
'pp': pp,
'basis': basis,
'pseudo_dir': pseudo_dir,
'basis_dir': basis_dir,
'init_wfc': 'atomic',
'init_chg': 'atomic',
'cal_force': 1,
'cal_stress': 1,
'out_stru': 1,
'out_chg': 0,
'out_mul': 0,
'out_wfc_lcao': 0,
'out_bandgap': 0,
}


if __name__ == "__main__":
# running process
# read initial guessed neb chain
init_chain = read(init_chain, index=':')
neb = AbacusNEB(init_chain, parameters=parameters, parallel=parallel,
directory=neb_directory, mpi=mpi, omp=omp, abacus=abacus,
algorism=algorism, k=k, dyneb=dyneb)
neb.run(optimizer=neb_optimizer, climb=climb, fmax=fmax)

Writing dyneb_run.py
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在终端内通过vim等方法,按如上方式编辑完成之后,即可调用python运行该程序,以实现ASE调用ABACUS进行过渡态计算,该过程耗时约2h,感兴趣的用户可以自行计算。去除下面的#号注释即可运行

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# !python3 dyneb_run.py
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我们直接来看计算输出,ATST-Tools的计算输出实际就是ASE在计算NEB过程中的输出,只是通过ATST-Tools,我们方便地调用了ABACUS作为ASE的计算单元

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cat ../dyneb/running_neb.out
Notice: Parallel calculation is not being used
Set NEB method to DyNEB automatically
----- Running Dynamic NEB -----
----- improvedtangent method is being used -----
----- Default scale_fmax = 1.0 -----
      Step     Time          Energy          fmax
FIRE:    0 18:28:24    -7051.845345         0.733359
FIRE:    1 18:34:09    -7051.879062         0.594320
FIRE:    2 18:39:55    -7051.922971         0.350617
FIRE:    3 18:45:23    -7051.949616         0.195919
FIRE:    4 18:50:57    -7051.951295         0.224455
FIRE:    5 18:56:39    -7051.952800         0.217455
FIRE:    6 19:04:29    -7051.955533         0.203700
FIRE:    7 19:12:16    -7051.958973         0.183747
FIRE:    8 19:19:13    -7051.962508         0.159008
FIRE:    9 19:24:39    -7051.965466         0.134910
FIRE:   10 19:30:23    -7051.967701         0.103314
FIRE:   11 19:35:58    -7051.968988         0.112794
FIRE:   12 19:41:36    -7051.969789         0.129614
FIRE:   13 19:47:16    -7051.970598         0.138944
FIRE:   14 19:52:55    -7051.972043         0.136817
FIRE:   15 19:58:38    -7051.974469         0.120972
FIRE:   16 20:04:24    -7051.977592         0.091176
FIRE:   17 20:09:53    -7051.980373         0.075211
FIRE:   18 20:11:43    -7051.981981         0.052248
FIRE:   19 20:13:33    -7051.982934         0.087704
FIRE:   20 20:17:14    -7051.984384         0.084422
FIRE:   21 20:22:44    -7051.985587         0.112840
FIRE:   22 20:26:29    -7051.985587         0.086535
FIRE:   23 20:28:27    -7051.985587         0.036730

=== n_max set to 0, automatically detect the images of chain by NEBTools ===
Number of images per band guessed to be 5.
num: 0; Energy: -7052.6037618 (eV)
num: 1; Energy: -7052.2767038 (eV)
num: 2; Energy: -7051.9855868 (eV)
num: 3; Energy: -7052.2797724 (eV)
num: 4; Energy: -7052.6035978 (eV)
Reaction Barrier and Energy Difference: (0.61817499999961, 0.00016400000004068715) (eV)
Number of images per band guessed to be 5.
Processing band         23 /         24
Appears to be only one band in the images.
Processing band          0 /          1
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直接运行python3 neb_run.py只会输出运行过程中的一系列时间-能量和力的结果,后续的NEB后处理通过调用ATST-Tools/neb目录下的neb_post.py完成

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# ! python3 /opt/ATST-Tools/neb/neb_post.py neb.traj
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经过neb_post.py后处理之后,输出结果出绝对能量信息外,会包括:

  • nebplots_chain.pdf,绘制了计算收敛时的NEB链能量-反应坐标曲线,并且该曲线上有各个映像的受力在反应坐标方向的投影,所做的能量-反应坐标曲线也是基于这个投影结果进行了拟合得到的。
  • neb.traj,存储了NEB计算过程中的所有计算轨迹。可以通过ase -T gui neb.traj可视化
reaction_diffusion

Li-diffu-Si 案例的计算结果

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并行运行需要对脚本进行一些修改,开启其并行特征。但最关键的还是在调用脚本的时候启动并行,并调整并行核数与NEB链的映像个数一致。

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cd ..
/opt/ATST-Tools/examples/Li-diffu-Si
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mkdir neb_para_example
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cd neb_para_example
/opt/ATST-Tools/examples/Li-diffu-Si/neb_para_example
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我们此前使用的init_neb_chain.traj是可以直接复用的。你没有想错,这也是利用ATST-Tools在计算NEB时做续算的关键。

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cp ../dyneb-example/init_neb_chain.traj .
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简单修改一下neb_run.py,改改核数与并行NEB相关参数即可

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%%writefile neb_run.py

# parallel NEB cannot be directly run in notebook

from ase.optimize import FIRE, BFGS
from ase.io import read, write
from abacus_neb import AbacusNEB

# setting
mpi = 5
omp = 1
fmax = 0.05 # eV / Ang
neb_optimizer = FIRE # suited for CI-NEB
neb_directory = "NEBrun"
algorism = "improvedtangent" # IT-NEB is recommended
climb = True
dyneb = False
parallel = True
k = 0.10 # eV/Ang^2, spring constant
init_chain = "init_neb_chain.traj"
abacus = "abacus"
#lib_dir = "/lustre/home/2201110432/example/abacus"
lib_dir = ""
pseudo_dir = f"{lib_dir}"
basis_dir = f"{lib_dir}"
pp = {
'Li':'C_ONCV_PBE-1.2.upf',
'Si':'H_ONCV_PBE-1.2.upf',
}
basis = {
'Li': 'Li_gga_8au_100Ry_4s1p.orb',
'Si': 'Si_gga_8au_100Ry_2s2p1d.orb',
,}
kpts = [2, 2, 2]
parameters = {
'calculation': 'scf',
'nspin': 1,
'xc': 'pbe',
'ecutwfc': 100,
'dft_functional': 'pbe',
'ks_solver': 'genelpa',
'symmetry': 0,
'vdw_method': 'none',
'smearing_method': 'gaussian',
'smearing_sigma': 0.001,
'basis_type': 'lcao',
'mixing_type': 'broyden',
'scf_thr': 1e-6,
'scf_nmax': 100,
'kpts': kpts,
'pp': pp,
'basis': basis,
'pseudo_dir': pseudo_dir,
'basis_dir': basis_dir,
'init_wfc': 'atomic',
'init_chg': 'atomic',
'cal_force': 1,
'cal_stress': 1,
'out_stru': 1,
'out_chg': 0,
'out_mul': 0,
'out_wfc_lcao': 0,
'out_bandgap': 0,
}


if __name__ == "__main__":
# running process
# read initial guessed neb chain
init_chain = read(init_chain, index=':')
neb = AbacusNEB(init_chain, parameters=parameters, parallel=parallel,
directory=neb_directory, mpi=mpi, omp=omp, abacus=abacus,
algorism=algorism, k=k, dyneb=dyneb)
neb.run(optimizer=neb_optimizer, climb=climb, fmax=fmax)
Writing neb_run.py
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在终端准备好脚本之后,即可通过mpirun gpaw python进行并行NEB计算。当然了,其中的ABACUS也是用mpirun调用的,这两个mpirun需要对应同一个mpirun程序,你的镜像应该帮你准备好了。如果你有兴趣的话,可以去掉下面的注释,直接跑跑——当然这需要至少16核的计算环境

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[ ]
# ! mpirun -np 3 gpaw python neb_run.py
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我们直接来看计算结果

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cat ../neb/running_neb.out
----- Running ASE-NEB -----
----- improvedtangent method is being used -----
----- Parallel calculation is being used -----
      Step     Time          Energy          fmax
FIRE:    0 16:50:48    -7051.845345         0.733359
FIRE:    1 16:53:44    -7051.879062         0.594320
FIRE:    2 16:56:39    -7051.922971         0.350617
FIRE:    3 16:59:18    -7051.949616         0.195919
FIRE:    4 17:02:01    -7051.951295         0.224455
FIRE:    5 17:04:47    -7051.952800         0.217455
FIRE:    6 17:07:33    -7051.955533         0.203700
FIRE:    7 17:10:25    -7051.958973         0.183747
FIRE:    8 17:13:04    -7051.962508         0.159008
FIRE:    9 17:15:42    -7051.965466         0.134910
FIRE:   10 17:18:34    -7051.967701         0.103314
FIRE:   11 17:21:25    -7051.968988         0.112794
FIRE:   12 17:24:13    -7051.969789         0.129614
FIRE:   13 17:27:03    -7051.970598         0.138944
FIRE:   14 17:29:55    -7051.972043         0.136817
FIRE:   15 17:32:49    -7051.974469         0.120972
FIRE:   16 17:35:43    -7051.977592         0.091176
FIRE:   17 17:38:31    -7051.980373         0.075211
FIRE:   18 17:41:20    -7051.981840         0.058992
FIRE:   19 17:44:06    -7051.982561         0.090015
FIRE:   20 17:46:57    -7051.983863         0.090542
FIRE:   21 17:49:49    -7051.985435         0.047680

=== n_max set to 0, automatically detect the images of chain by NEBTools ===
Number of images per band guessed to be 5.
num: 0; Energy: -7052.6037618 (eV)
num: 1; Energy: -7052.277576 (eV)
num: 2; Energy: -7051.985435 (eV)
num: 3; Energy: -7052.2790721 (eV)
num: 4; Energy: -7052.6035978 (eV)
Reaction Barrier and Energy Difference: (0.6183268000004314, 0.00016400000004068715) (eV)
Number of images per band guessed to be 5.
Processing band         21 /         22
Appears to be only one band in the images.
Processing band          0 /          1
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上述过程基本上就是调用ATST-Tools进行NEB计算的全过程,这一过程在Slurm队列管理的服务器上可以更容易地运行,用户只需要使用ATST-Tools/neb下的neb_submit.sh脚本即可。同理,ATST-Tools中还提供了autoneb_submit.shdimer_submit.sh等适用于Slurm队列的shell脚本,帮助用户在服务器上快速运行ASE-ABACUS过渡态计算。

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我们来看一个更贴近催化计算实际的例子,Cy-Pt@graphene是环己烷在单原子Pt负载石墨烯上的解离

alt

进入到该文件夹中:

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cd /opt/ATST-Tools/examples/Cy-Pt@graphene
/opt/ATST-Tools/examples/Cy-Pt@graphene
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[9]
ls
autoneb/  data/  eb-neb/  it-neb/
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该案例的NEB采用8个image描述反应过程,并且由于环己烷分子的非极性性、负载石墨烯的柔性等因素,这一NEB计算是存在挑战的。如果直接去跑CI-NEB计算,一方面需要过大的计算量,另一方面也容易因为对过渡态的解析度不够,搜索到错误的反应路径和过渡态。本例中的it-neb采用的即是最常用的IT-NEB+CI-NEB的方法,但它所用NEB步数非常长,且收敛到了错误的结果

reaction_diffusion

Cy-Pt@graphene 案例的错误计算结果

至于如何判断过渡态本身是正确的还是错误的,一个简单的方法是直接看图。ASE的NEB后处理模块NEBTools中的作图模块是会在图中以切线的形式,画出结构在反应坐标方向的受力的投影的,在能量最高点,如果它是一个正确的过渡态,这个投影切线会是基本水平的。当然,最终还是要通过振动计算得到反应坐标方向的单一虚频来进行验证。这个振动计算可以通过phonopy或者ASE完成,在ATST-Tools当前版本(1.3.1)中集成了ASE的振动计算和热力学较正方法,后续会有介绍。

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于是,我们可以采用AutoNEB方法,一方面减少计算量,另一方面提升过渡态附近的解析度,从而在更高的计算效率下计算出正确的过渡态。

进行这一AutoNEB计算可以分为如下几个步骤

  1. 准备所需的初末态计算结果,以及计算所需的赝势和轨道文件
  2. 通过neb_make.py生成初猜结构
  3. 通过autoneb_run.py设置计算参数并开展计算

让我们开始吧

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mkdir autoneb_test
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cd autoneb_test
/opt/ATST-Tools/examples/Cy-Pt@graphene/autoneb_test
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[35]
cp -r ../data/* .
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[36]
ls
C_ONCV_PBE-1.0.upf          H_gga_6au_100Ry_2s1p.orb
C_gga_7au_100Ry_2s2p1d.orb  IS/
CyPt-ISFS.tar.gz            Pt_ONCV_PBE-1.0.upf
FS/                         Pt_gga_7au_100Ry_4s2p2d1f.orb
H_ONCV_PBE-1.0.upf
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[37]
# 生成初猜,采用4个image作为AutoNEB的初始image数与并行进程数
! python3 /opt/ATST-Tools/neb/neb_make.py IS/OUT.ABACUS/running_relax.log FS/OUT.ABACUS/running_relax.log 4
----- Get NEB guess chain only by initial and final state -----
--- Successfully make guessed image chain by idpp method ! ---
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# 复制已有的autoneb_run.py并查看
! cp /opt/ATST-Tools/neb/autoneb_run.py .
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cat autoneb_run.py
# JamesMisaka in 2023-11-27
# Run AutoNEB calculation by ASE-ABACUS
# part of ATST-Tools scripts


from ase.optimize import FIRE, BFGS
from ase.io import read, write
from ase.parallel import world, parprint, paropen
#from pathlib import Path
from abacus_autoneb import AbacusAutoNEB

# setting
mpi = 16
omp = 4
neb_optimizer = FIRE # suited for CI-NEB
neb_directory = "AutoNEBrun"
# algorism = 'eb' # default for AutoNEB
algorism = "improvedtangent" # IT-NEB
init_chain = "init_neb_chain.traj"
climb = True
fmax = [0.20, 0.05]  # eV / Ang, 2 fmax for others and last CI-NEB in all-images
n_simul = world.size # only for autoneb, number of simultaneous calculation
n_images = 10 # only for autoneb, max number of all image, which should be reached
smooth_curve = False # True to do more neb step to smooth the curve.
k = 0.10 # eV/Ang^2, force constant of spring, 0.05 is from VTST-Tools
abacus = "abacus"
#lib_dir = "/lustre/home/2201110432/example/abacus"
lib_dir = ""
pseudo_dir = f"{lib_dir}/"
basis_dir = f"{lib_dir}/"
pp = {
      'C':'C_ONCV_PBE-1.0.upf',
      'H':'H_ONCV_PBE-1.0.upf',
      'Pt':'Pt_ONCV_PBE-1.0.upf',
      }
basis = {
         'C': 'C_gga_7au_100Ry_2s2p1d.orb',
         'H': 'H_gga_6au_100Ry_2s1p.orb',
         'Pt': 'Pt_gga_7au_100Ry_4s2p2d1f.orb'
         ,}
kpts = [2, 1, 2]
parameters = {
    'calculation': 'scf',
    'nspin': 2,
    'xc': 'pbe',
    'ecutwfc': 100,
    'dft_functional': 'pbe',
    'ks_solver': 'genelpa',
    'symmetry': 0,
    'vdw_method': 'd3_bj',
    'smearing_method': 'gaussian',
    'smearing_sigma': 0.001,
    'basis_type': 'lcao',
    'mixing_type': 'broyden',
    'scf_thr': 1e-6,
    'scf_nmax': 100,
    'kpts': kpts,
    'pp': pp,
    'basis': basis,
    'pseudo_dir': pseudo_dir,
    'basis_dir': basis_dir,
    'cal_force': 1,
    'cal_stress': 1,
    'init_wfc': 'atomic',
    'init_chg': 'atomic',
    'out_stru': 1,
    'out_chg': 0,
    'out_mul': 0,
    'out_wfc_lcao': 0,
    'out_bandgap': 0,
    'efield_flag': 1,
    'dip_cor_flag': 1,
    'efield_dir': 1,
    'efield_pos_max': 0.0
}


if __name__ == "__main__": 
# running process
# read initial guessed neb chain
    init_chain = read(init_chain, index=':')
    neb = AbacusAutoNEB(init_chain, parameters, algorism=algorism, 
                        directory=neb_directory, k=k,
                        n_simul=n_simul, n_max=n_images, 
                        abacus=abacus,  mpi=mpi, omp=omp, )
    neb.run(optimizer=neb_optimizer, climb=climb, 
                fmax=fmax, smooth_curve=smooth_curve)
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这一脚本的内容已经基本满足了对该实例进行AutoNEB的需要,用户可以通过上面提到的方法,简单微调以下改脚本的相关设置即可进行AutoNEB计算。运行方式也是一样的

mpirun -np 4 gpaw python autoneb_run.py

我们直接来看结果。

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[1]
cd opt/ATST-Tools/examples/Cy-Pt@graphene/autoneb
/opt/ATST-Tools/examples/Cy-Pt@graphene/autoneb
/usr/local/lib/python3.10/dist-packages/IPython/core/magics/osm.py:417: UserWarning: using dhist requires you to install the `pickleshare` library.
  self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
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[44]
# 显示运行结果文件
! ls
AutoNEB_iter	     run_autoneb000.traj  run_autoneb006.traj
autoneb_run.py	     run_autoneb001.traj  run_autoneb007.traj
autoneb_submit.sh    run_autoneb002.traj  run_autoneb008.traj
init_neb_chain.traj  run_autoneb003.traj  run_autoneb009.traj
neb_latest.traj      run_autoneb004.traj  running_autoneb.out
nebplots_all.pdf     run_autoneb005.traj  vib_analysis_TS
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# 查看整体运算结果,注意该运算结果实际是用autoneb_submit.sh得到的
! cat running_autoneb.out
Loading mkl version 2023.0.0
Loading tbb version 2021.8.0
Loading compiler-rt version 2023.0.0
Loading mpi version 2021.8.0
Loading compiler version 2023.0.0
Loading oclfpga version 2023.0.0
  Load "debugger" to debug DPC++ applications with the gdb-oneapi debugger.
  Load "dpl" for additional DPC++ APIs: https://github.com/oneapi-src/oneDPL

Loading abacus/3.4.2-icx
  Loading requirement: tbb/latest compiler-rt/latest mkl/2023.0.0 mpi/latest
    oclfpga/latest compiler/latest
NSIMUL is 4
===== AutoNEB Job Starting =====
 ===== Make Initial NEB Guess =====
---- Fix Atoms below 0.0 in direction y ----
---- Set initial magmom for [] to [] ----
---- Fix Atoms below 0.0 in direction y ----
---- Set initial magmom for [] to [] ----
---- Fix Atoms below 0.0 in direction y ----
---- Set initial magmom for [] to [] ----
---- Fix Atoms below 0.0 in direction y ----
---- Set initial magmom for [] to [] ----
--- Successfully make guessed image chain by idpp method ! ---
===== Running AutoNEB =====
Notice: AutoNEB method is set
You manually set n_simul = 4, n_max = 10
----- Running AutoNEB -----
----- improvedtangent method is being used -----
The NEB initially has 6 images  (including the end-points)
Start of evaluation of the initial images
Now starting iteration 1 on  [0, 1, 2, 3, 4, 5]
Finished initialisation phase.
****Now adding another image until n_max is reached (6/10)****
Adding image between 2 and 3. New image point is selected on the basis of the biggest spring length!
Now starting iteration 2 on  [1, 2, 3, 4, 5, 6]
****Now adding another image until n_max is reached (7/10)****
Adding image between 1 and 2. New image point is selected on the basis of the biggest spring length!
Now starting iteration 3 on  [1, 2, 3, 4, 5, 6]
****Now adding another image until n_max is reached (8/10)****
Adding image between 5 and 6. New image point is selected on the basis of the biggest spring length!
Now starting iteration 4 on  [2, 3, 4, 5, 6, 7]
****Now adding another image until n_max is reached (9/10)****
Adding image between 7 and 8. New image point is selected on the basis of the biggest spring length!
Now starting iteration 5 on  [4, 5, 6, 7, 8, 9]
n_max images has been reached
****Now doing the CI-NEB calculation****
Now starting iteration 6 on  [2, 3, 4, 5, 6, 7]
----- AutoNEB calculation finished -----
===== AutoNEB Process Done ! =====
===== Running Post-Processing =====
=== n_max set to 0, automatically detect the images of chain by NEBTools ===
Appears to be only one band in the images.
num: 0; Energy: -11866.824886 (eV)
num: 1; Energy: -11866.82722 (eV)
num: 2; Energy: -11866.801706 (eV)
num: 3; Energy: -11866.78262 (eV)
num: 4; Energy: -11866.587954 (eV)
num: 5; Energy: -11865.497 (eV)
num: 6; Energy: -11866.330196 (eV)
num: 7; Energy: -11866.396832 (eV)
num: 8; Energy: -11866.429487 (eV)
num: 9; Energy: -11866.435419 (eV)
Reaction Barrier and Energy Difference: (1.3278860000009587, 0.3894670000008773) (eV)
Appears to be only one band in the images.
Processing band          0 /          1
===== Done ! =====
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# 查看AutoNEB中第一步NEB的计算结果
! cat AutoNEB_iter/run_autoneb_log_iter001.log
      Step     Time          Energy          fmax
FIRE:    0 00:35:21   -11864.578532         3.642360
FIRE:    1 00:36:10   -11864.782954         2.870872
FIRE:    2 00:36:56   -11865.029191         2.407401
FIRE:    3 00:37:40   -11865.183575         3.420662
FIRE:    4 00:38:26   -11865.149576         4.842759
FIRE:    5 00:39:11   -11865.185455         3.786428
FIRE:    6 00:40:01   -11865.238631         2.154321
FIRE:    7 00:40:47   -11865.284643         1.979722
FIRE:    8 00:41:33   -11865.307675         1.889517
FIRE:    9 00:42:20   -11865.309583         1.742232
FIRE:   10 00:43:06   -11865.304529         1.941274
FIRE:   11 00:43:51   -11865.305786         1.824236
FIRE:   12 00:44:39   -11865.321340         1.566756
FIRE:   13 00:45:26   -11865.351452         1.232224
FIRE:   14 00:46:12   -11865.385412         1.163525
FIRE:   15 00:47:00   -11865.405953         1.863983
FIRE:   16 00:47:46   -11865.411933         1.196430
FIRE:   17 00:48:34   -11865.426725         1.069129
FIRE:   18 00:49:19   -11865.431487         0.961849
FIRE:   19 00:50:06   -11865.439472         0.760762
FIRE:   20 00:50:51   -11865.448191         0.517175
FIRE:   21 00:51:39   -11865.455199         0.459462
FIRE:   22 00:52:25   -11865.459289         0.472398
FIRE:   23 00:53:13   -11865.460873         0.431848
FIRE:   24 00:54:00   -11865.461725         0.539257
FIRE:   25 00:54:45   -11865.463809         0.619627
FIRE:   26 00:55:31   -11865.468630         0.598042
FIRE:   27 00:56:20   -11865.476511         0.468127
FIRE:   28 00:57:07   -11865.485968         0.365569
FIRE:   29 00:57:53   -11865.494549         0.412251
FIRE:   30 00:58:43   -11865.501988         0.385664
FIRE:   31 00:59:30   -11865.511484         0.422284
FIRE:   32 01:00:16   -11865.525009         0.366845
FIRE:   33 01:01:02   -11865.539757         0.231356
FIRE:   34 01:01:50   -11865.554350         0.309826
FIRE:   35 01:02:39   -11865.570950         0.294388
FIRE:   36 01:03:24   -11865.590207         0.275131
FIRE:   37 01:04:08   -11865.611798         0.247073
FIRE:   38 01:04:53   -11865.636943         0.299314
FIRE:   39 01:05:39   -11865.672444         0.295211
FIRE:   40 01:06:26   -11865.724616         0.398352
FIRE:   41 01:07:17   -11865.809261         0.672083
FIRE:   42 01:08:02   -11865.836765         0.677076
FIRE:   43 01:08:49   -11865.840971         0.681209
FIRE:   44 01:09:39   -11865.848278         0.688700
FIRE:   45 01:10:27   -11865.858156         0.697759
FIRE:   46 01:11:13   -11865.871159         0.704303
FIRE:   47 01:11:59   -11865.887878         0.703259
FIRE:   48 01:12:47   -11865.907860         0.688451
FIRE:   49 01:13:34   -11865.929898         0.651860
FIRE:   50 01:14:24   -11865.955356         0.574260
FIRE:   51 01:15:10   -11865.982482         0.436765
FIRE:   52 01:15:55   -11866.006105         0.314752
FIRE:   53 01:16:44   -11866.020034         0.413740
FIRE:   54 01:17:31   -11866.025234         0.697364
FIRE:   55 01:18:18   -11866.027275         0.653814
FIRE:   56 01:19:01   -11866.030891         0.572655
FIRE:   57 01:19:46   -11866.035293         0.464302
FIRE:   58 01:20:32   -11866.039733         0.341400
FIRE:   59 01:21:23   -11866.043688         0.219902
FIRE:   60 01:22:07   -11866.046996         0.200859
FIRE:   61 01:22:55   -11866.049775         0.236517
FIRE:   62 01:23:41   -11866.052505         0.255194
FIRE:   63 01:24:30   -11866.055451         0.245242
FIRE:   64 01:25:18   -11866.058968         0.220082
FIRE:   65 01:26:06   -11866.063303         0.193788
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[2]
# 查看AutoNEB中最后一步CI-NEB的计算结果
! cat AutoNEB_iter/run_autoneb_log_iter006.log
      Step     Time          Energy          fmax
FIRE:    0 01:57:54   -11866.084572         0.652487
FIRE:    1 01:58:40   -11866.076705         0.676456
FIRE:    2 01:59:28   -11866.059007         0.715741
FIRE:    3 02:00:13   -11866.028561         0.745702
FIRE:    4 02:00:59   -11865.982395         0.745921
FIRE:    5 02:01:46   -11865.918309         0.713379
FIRE:    6 02:02:36   -11865.835733         0.659343
FIRE:    7 02:03:21   -11865.736940         0.602895
FIRE:    8 02:04:09   -11865.616163         0.570285
FIRE:    9 02:04:56   -11865.486295         0.576872
FIRE:   10 02:05:41   -11865.366292         0.553076
FIRE:   11 02:06:26   -11865.290706         0.491710
FIRE:   12 02:07:10   -11865.268212         0.382165
FIRE:   13 02:07:56   -11865.295327         0.349660
FIRE:   14 02:08:42   -11865.381779         0.505350
FIRE:   15 02:09:29   -11865.389766         0.478347
FIRE:   16 02:10:14   -11865.402261         0.431838
FIRE:   17 02:11:01   -11865.414176         0.381902
FIRE:   18 02:11:46   -11865.421392         0.382459
FIRE:   19 02:12:33   -11865.422792         0.386433
FIRE:   20 02:13:18   -11865.419163         0.378440
FIRE:   21 02:14:05   -11865.411475         0.372510
FIRE:   22 02:14:52   -11865.399699         0.363692
FIRE:   23 02:15:36   -11865.382875         0.311966
FIRE:   24 02:16:22   -11865.360650         0.348324
FIRE:   25 02:17:08   -11865.335546         0.494877
FIRE:   26 02:17:55   -11865.316262         0.735960
FIRE:   27 02:18:45   -11865.307194         1.100647
FIRE:   28 02:19:30   -11865.309266         0.196186
FIRE:   29 02:20:19   -11865.313339         0.909086
FIRE:   30 02:21:08   -11865.313751         0.707882
FIRE:   31 02:21:54   -11865.314565         0.350729
FIRE:   32 02:22:42   -11865.315812         0.178845
FIRE:   33 02:23:30   -11865.315906         0.178576
FIRE:   34 02:24:16   -11865.316091         0.178013
FIRE:   35 02:25:07   -11865.316373         0.177024
FIRE:   36 02:25:57   -11865.316741         0.175838
FIRE:   37 02:26:45   -11865.317208         0.174313
FIRE:   38 02:27:32   -11865.317762         0.172504
FIRE:   39 02:28:19   -11865.318410         0.170232
FIRE:   40 02:29:08   -11865.319231         0.167451
FIRE:   41 02:29:54   -11865.320258         0.163917
FIRE:   42 02:30:40   -11865.321550         0.165854
FIRE:   43 02:31:28   -11865.323145         0.171715
FIRE:   44 02:32:18   -11865.325136         0.179361
FIRE:   45 02:33:07   -11865.327600         0.188798
FIRE:   46 02:33:54   -11865.330675         0.200416
FIRE:   47 02:34:43   -11865.334504         0.213338
FIRE:   48 02:35:32   -11865.339264         0.226164
FIRE:   49 02:36:21   -11865.345094         0.234130
FIRE:   50 02:37:09   -11865.352065         0.232614
FIRE:   51 02:37:54   -11865.360183         0.216983
FIRE:   52 02:38:43   -11865.369363         0.185817
FIRE:   53 02:39:29   -11865.379371         0.148843
FIRE:   54 02:40:14   -11865.389614         0.138991
FIRE:   55 02:40:59   -11865.399380         0.137180
FIRE:   56 02:41:45   -11865.408222         0.165171
FIRE:   57 02:42:32   -11865.416086         0.203523
FIRE:   58 02:43:19   -11865.423394         0.231605
FIRE:   59 02:44:06   -11865.430772         0.247774
FIRE:   60 02:44:53   -11865.438325         0.254307
FIRE:   61 02:45:41   -11865.445080         0.267498
FIRE:   62 02:46:29   -11865.448719         0.881362
FIRE:   63 02:47:15   -11865.451780         0.231961
FIRE:   64 02:48:02   -11865.452007         0.231221
FIRE:   65 02:48:48   -11865.452438         0.229862
FIRE:   66 02:49:34   -11865.453071         0.227879
FIRE:   67 02:50:21   -11865.453876         0.225257
FIRE:   68 02:51:08   -11865.454816         0.222156
FIRE:   69 02:52:00   -11865.455865         0.218612
FIRE:   70 02:52:44   -11865.457001         0.214634
FIRE:   71 02:53:30   -11865.458341         0.209595
FIRE:   72 02:54:15   -11865.459892         0.203370
FIRE:   73 02:55:01   -11865.461651         0.195673
FIRE:   74 02:55:49   -11865.463637         0.186376
FIRE:   75 02:56:36   -11865.465861         0.175254
FIRE:   76 02:57:22   -11865.468343         0.162491
FIRE:   77 02:58:09   -11865.471156         0.147879
FIRE:   78 02:58:58   -11865.474326         0.131731
FIRE:   79 02:59:44   -11865.477956         0.114483
FIRE:   80 03:00:31   -11865.482135         0.096221
FIRE:   81 03:01:17   -11865.486787         0.084464
FIRE:   82 03:02:05   -11865.491684         0.134461
FIRE:   83 03:02:50   -11865.496380         0.273588
FIRE:   84 03:03:36   -11865.496522         0.051535
FIRE:   85 03:04:21   -11865.496806         0.203176
FIRE:   86 03:05:08   -11865.496838         0.161525
FIRE:   87 03:05:53   -11865.496901         0.086825
FIRE:   88 03:06:42   -11865.497000         0.040039
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这样计算出来的就是正确的过渡态,我们可以在命令行中使用ase -T gui来进行可视化,也可以采用如下的方法

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[4]
from ase.io import read
from ase.visualize import view

atoms = read("./run_autoneb005.traj")
view(atoms)
<Popen: returncode: None args: ['/usr/bin/python3', '-m', 'ase', 'gui', '-']>
usage: ase [-h] [--version] [-T]
           {help,info,test,gui,db,run,band-structure,build,dimensionality,eos,ulm,find,nebplot,nomad-upload,nomad-get,convert,reciprocal,completion,diff,exec}
           ...
ase: error: ModuleNotFoundError: No module named 'tkinter'
To get a full traceback, use: ase -T gui ...
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与此同时,在neb_post.py处理之后

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[ ]
# ! python3 ~/opt/ATST-Tools/neb/neb_post.py --autoneb run_autoneb???.traj
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所生成的nebplots_all.pdf很好地给出了当前的NEB反应路径对应的势能-反应坐标曲线,从此时的曲线中不难看出如此计算得到的过渡态已然正确,并且过渡态邻近的点更为靠近过渡态。

reaction_diffusion

Cy-Pt@graphene 案例经AutoNEB方法得到的正确计算结果

振动计算(频率分析)表明该过渡态确实只在反应坐标方向存在单一虚频,具体结过将在后续展示。

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经过以上这些例子,相信你已经完全掌握了基于ATST-Tools的组织方法,采用ASE-ABACUS接口完成NEB以及AutoNEB过渡态搜索计算了。使用dimer等其他方法也是类似的道理。

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2.3 通过ATST-Tools进行振动计算和自由能较正

在计算均相或多相的化学反应时,我们在通过结构优化和过渡态搜索方法,得到反应的初末态和过渡态的能量和电子结构信息的基础之上,还会关心:

  • 我们得到的初末态优化结构是否是稳定结构?即该优化结构是否具有虚频
  • 我们得到的过渡态是否是正确的过渡态结构?即该过渡态是否具有沿反应路径的单一虚频
  • 我们能否考虑除零温电子能量之外的其他统计热力学信息,比如零点能,以及适当的振动自由能校正。

这些事情需要通过振动计算(又称声子计算)来完成。其方法通常有两种,一是线性响应法,二是有限差分法。其中,最常用的是有限差分法,它通过生成一系列的微扰结构,基于结构间各原子的坐标差和受力差,通过有限差分的方法求得对应原子的Hessian贡献,进而求得振动模式。

ATST-Tools中集成了使用ASE-ABACUS基于有限差分进行振动计算的方法。该工作流实际上只使用了一个脚本,我们可以直接查看

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[11]
cat /opt/ATST-Tools/vibration/vib_analysis.py
# JamesMisaka in 2023-11-30
# Vibrational analysis from finite displacement by using abacus
# part of ATST-Tools scripts

import os
import numpy as np
from ase.vibrations import Vibrations
from ase.thermochemistry import HarmonicThermo
from ase.io import read, write
from ase.calculators.abacus import Abacus, AbacusProfile
from ase.parallel import world, parprint

stru = "STRU"
atoms = read(stru)
# indices setting for which atoms to be displaced
#vib_indices = [atom.index for atom in atoms if atom.symbol == 'H']
vib_indices = [0, 1, 37]
T = 523.15 # K

vib_name = 'vib'
delta = 0.01
nfree = 2

abacus = "abacus"
mpi = 16
omp = 4
lib_dir = "/lustre/home/2201110432/example/abacus"
pseudo_dir = f"{lib_dir}/PP"
basis_dir = f"{lib_dir}/ORB"
pp = {
      'H': 'H_ONCV_PBE-1.0.upf',
      'C': 'C_ONCV_PBE-1.0.upf',
      'O': 'O_ONCV_PBE-1.0.upf',
      'Fe': 'Fe_ONCV_PBE-1.0.upf',
      }
basis = {
         'H': 'H_gga_6au_100Ry_2s1p.orb',
         'C': 'C_gga_7au_100Ry_2s2p1d.orb',
         'O': 'O_gga_7au_100Ry_2s2p1d.orb',
         'Fe': 'Fe_gga_8au_100Ry_4s2p2d1f.orb'
         ,}
kpts = [3, 1, 2]
parameters = {
    'calculation': 'scf',
    'nspin': 2,
    'xc': 'pbe',
    'ecutwfc': 100,
    'ks_solver': 'genelpa',
    'symmetry': 0,
    'vdw_method': 'none',
    'smearing_method': 'mp',
    'smearing_sigma': 0.002,
    'basis_type': 'lcao',
    'mixing_type': 'broyden',
    'scf_thr': 1e-7,
    'scf_nmax': 300,
    'kpts': kpts,
    'pp': pp,
    'basis': basis,
    'pseudo_dir': pseudo_dir,
    'basis_dir': basis_dir,
    'init_chg': 'atomic',
    'init_wfc': 'file',
    'cal_force': 1,
    'cal_stress': 1,
    'out_stru': 1,
    'out_chg': 1,
    'out_mul': 0,
    'out_bandgap': 0,
    'out_wfc_lcao': 1,
    'efield_flag': 1,
    'dip_cor_flag': 1,
    'efield_dir': 1,
    'efield_pos_max': 0.7
}


def set_calculator(abacus, parameters, mpi=1, omp=1) -> Abacus:
    """Set Abacus calculators"""
    os.environ['OMP_NUM_THREADS'] = f'{omp}'
    profile = AbacusProfile(
        argv=['mpirun', '-np', f'{mpi}', abacus])
    out_directory = f"SCF-rank{world.rank}"
    calc = Abacus(profile=profile, directory=out_directory,
                **parameters)
    return calc

if __name__ == "__main__":
    print("==> Starting Vibrational Analysis <==")

    atoms.calc = set_calculator(abacus, parameters, mpi=mpi, omp=omp)

    vib = Vibrations(atoms, indices=vib_indices, 
                    name=vib_name, delta=delta, nfree=nfree)

    print("==> Running Vibrational Analysis <==")
    vib.run()
    # post-processing
    print("==> Done !!! <==")
    print(f"==> All force cache will be in {vib_name} directory <==")
    print("==> Vibrational Analysis Summary <==")
    vib.summary()
    print("==> Writing All Mode Trajectory <==")
    vib.write_mode()
    # thermochemistry
    print("==> Doing Harmonmic Thermodynamic Analysis <==")
    real_vib_energies = np.array([energy for energy in vib.get_energies() 
                        if energy.imag == 0 and energy.real > 0], dtype=float)
    thermo = HarmonicThermo(real_vib_energies)
    entropy = thermo.get_entropy(T)
    free_energy = thermo.get_helmholtz_energy(T)
    print(f"==> Entropy: {entropy:.6e} eV/K <==")
    print(f"==> Free Energy: {free_energy:.6f} eV <==")
    

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最关键的一点在于选择需要进行有限差分和计算振动模的原子。实际上,严格的振动模计算肯定是需要对晶胞内所有原子进行有限差分的,但由于针对表面催化体系,我们实际上只关心那些直接参与反应的部分原子的振动模,从而我们只需要选择一部分原子即可。

在选定需要进行有限差分计算的原子序号,以及使用ASE进行振动校正与自由能计算,和调用ABACUS计算的相关参数之后,可以直接通过

python3 vib_analysis.py

调用ABACUS进行振动计算。

我们可以直接看看针对上一解离反应过渡态的计算结果

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[12]
cd /opt/ATST-Tools/examples/Cy-Pt@graphene/autoneb/vib_analysis_TS
/opt/ATST-Tools/examples/Cy-Pt@graphene/autoneb/vib_analysis_TS
/usr/local/lib/python3.10/dist-packages/IPython/core/magics/osm.py:417: UserWarning: using dhist requires you to install the `pickleshare` library.
  self.shell.db['dhist'] = compress_dhist(dhist)[-100:]
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[13]
ls
JobRun.state      vib.14.traj  vib.26.traj  vib.38.traj  vib.5.traj
ase_sort.dat      vib.15.traj  vib.27.traj  vib.39.traj  vib.50.traj
neb_latest.traj   vib.16.traj  vib.28.traj  vib.4.traj   vib.51.traj
neb_latest_CIFs/  vib.17.traj  vib.29.traj  vib.40.traj  vib.52.traj
running_vib.err   vib.18.traj  vib.3.traj   vib.41.traj  vib.53.traj
running_vib.out   vib.19.traj  vib.30.traj  vib.42.traj  vib.6.traj
vib/              vib.2.traj   vib.31.traj  vib.43.traj  vib.7.traj
vib.0.traj        vib.20.traj  vib.32.traj  vib.44.traj  vib.8.traj
vib.1.traj        vib.21.traj  vib.33.traj  vib.45.traj  vib.9.traj
vib.10.traj       vib.22.traj  vib.34.traj  vib.46.traj  vib_analysis.py
vib.11.traj       vib.23.traj  vib.35.traj  vib.47.traj
vib.12.traj       vib.24.traj  vib.36.traj  vib.48.traj
vib.13.traj       vib.25.traj  vib.37.traj  vib.49.traj
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计算结果包括:

  • running_vib.out 即标准输出,输出了频率计算过程与结果
  • vib.*.traj 以轨迹形式输出了计算所得的各个振动模式的动画
  • vib文件夹,里面以JSON格式存储了计算所得的各个不同结构的能量与原子受力,用于程序复用,在下一次输出振动分析结果,或更换温度等条件进行自由能校正计算时不需要重新调用ABACUS进行计算

至于neb_latest.traj则是上一步AutoNEB计算所得的NEB轨迹,可以通过ATST-Tools中的如下脚本将其拆分为CIF等格式的结构文件

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[17]
# 先remove一下
! rm -rf neb_latest_CIFs/
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[18]
! python3 /opt/ATST-Tools/neb/traj_transform.py neb_latest.traj cif
===> Successfully Transform NEB Traj to cif files ! <===
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查看running_vib.out,我们即可获取关于此结构进行振动计算和自由能校正的所得信息

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[19]
cat running_vib.out
Loading mkl version 2023.0.0
Loading tbb version 2021.8.0
Loading compiler-rt version 2023.0.0
Loading mpi version 2021.8.0
Loading compiler version 2023.0.0
Loading oclfpga version 2023.0.0
  Load "debugger" to debug DPC++ applications with the gdb-oneapi debugger.
  Load "dpl" for additional DPC++ APIs: https://github.com/oneapi-src/oneDPL

Loading abacus/3.4.3-icx-dev
  Loading requirement: tbb/latest compiler-rt/latest mkl/latest mpi/latest
    oclfpga/latest compiler/latest
Vibrational Calculation Start !
==> Running Vibrational Analysis <==
==> Get Energy and Frequency <==
==> Get ZPE <==
==> Writing Trajectory <==
==> Summary <==
---------------------
  #    meV     cm^-1
---------------------
  0   87.4i    705.0i
  1    2.4      19.3
  2    3.5      28.3
  3    6.1      48.9
  4   14.5     117.2
  5   17.4     140.7
  6   20.9     168.5
  7   30.4     244.9
  8   38.7     312.0
  9   51.0     411.6
 10   53.1     428.5
 11   57.8     466.1
 12   65.3     526.4
 13   79.5     641.3
 14   96.8     781.1
 15   98.2     791.9
 16  102.3     825.1
 17  107.3     865.6
 18  108.3     873.4
 19  111.7     900.6
 20  120.9     975.1
 21  123.8     998.4
 22  129.7    1045.8
 23  131.5    1060.4
 24  132.7    1070.3
 25  137.3    1107.4
 26  144.5    1165.2
 27  151.3    1220.2
 28  153.9    1241.2
 29  155.6    1255.2
 30  158.1    1275.4
 31  159.4    1285.7
 32  163.2    1316.1
 33  163.7    1320.7
 34  165.8    1337.5
 35  166.6    1343.8
 36  167.1    1348.0
 37  178.3    1438.0
 38  178.9    1442.9
 39  179.2    1445.6
 40  179.8    1450.5
 41  181.3    1462.1
 42  263.0    2121.5
 43  362.0    2920.0
 44  366.9    2959.6
 45  367.8    2966.6
 46  368.1    2968.8
 47  369.0    2976.1
 48  371.0    2992.1
 49  373.5    3012.7
 50  374.4    3019.4
 51  374.7    3022.4
 52  375.8    3031.3
 53  377.5    3044.9
---------------------
Zero-point energy: 4.416 eV
===== Done at Wed Nov 29 23:13:33 CST 2023! =====
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可以看到该结构确实只具有单一虚频。查看vib.0.traj轨迹文件,可证实该振动模式沿反应坐标方向。于是我们便完成了振动计算和自由能校正。

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3. 总结

通过本Notebook,你学到了:

  1. 过渡态理论与过渡态搜索的基础知识
  2. 通过ATST-Tools,基于ASE和ASE-ABACUS接口完成以NEB和AutoNEB为例的过渡态搜索计算,包括预处理,具体计算与后处理过程。
  3. 对计算所得过渡态进行振动分析和自由能较正,确保过渡态正确,且得到其包含有振动自由度项的自由能较正结果。

如果你对过渡态与过渡态搜索产生了更多兴趣,或者有更多见解,欢迎一起讨论!

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