VASP Tutorials

https://vasp.at/tutorials/latest
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### Set VASP Path and Tutorials Directory

Source: https://vasp.at/tutorials/latest/index

These commands set environment variables for the VASP executable path and the tutorials working directory. Ensure you replace 'path/to/vasp.X.X.X/bin' and 'path/to/tutorials/working/directory' with your actual paths.

```bash
#!/bin/bash
export PATH=$PATH:path/to/vasp.X.X.X/bin
export TUTORIALS="path/to/tutorials/working/directory"
```

--------------------------------

### Launch JupyterLab

Source: https://vasp.at/tutorials/latest/index

This command initiates a JupyterLab server, typically used for interactive coding and data analysis with Jupyter notebooks. It opens a web-based interface in your browser for managing notebooks and terminals.

```bash
jupyter lab
```

--------------------------------

### Display Help for mpirun

Source: https://vasp.at/tutorials/latest/index

This command shows the help information for the 'mpirun' command, which is commonly used for running parallel applications. It provides an overview of available options and their usage.

```bash
mpirun --help
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/md/part1

Navigates to the example directory and executes the VASP standard executable using mpirun. This command requires VASP to be installed and configured for parallel execution.

```bash
cd $TUTORIALS/MD/e03_*
mpirun -np 4 vasp_std
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/bulk/part1

This command navigates to the example's directory and initiates a VASP calculation using mpirun. It requires VASP to be installed and configured for parallel execution. The output is written to files like OUTCAR.

```bash
cd $TUTORIALS/bulk/e02_*
mpirun -np 2 vasp_std
```

--------------------------------

### Navigate to Example Directory

Source: https://vasp.at/tutorials/latest/transition_states/part1

Changes the current directory to the specific example's location within the tutorials directory. This is a prerequisite for running the subsequent commands.

```bash
cd $TUTORIALS/transition_states/e04_*

```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/surface/part2

This snippet demonstrates how to navigate to the VASP example directory, copy necessary files, and initiate a VASP calculation using mpirun. It assumes VASP and mpirun are installed and accessible in the environment.

```bash
cd $TUTORIALS/surface/e08_*
cp $TUTORIALS/surface/e05_*/CHGCAR .
mpirun -np 4 vasp_std
```

--------------------------------

### Rename a File (Example)

Source: https://vasp.at/tutorials/latest/index

This command demonstrates renaming a file, using 'OUTCAR' as an example to 'OUTCAR.ref'. This is useful for preserving specific output files before running cleanup scripts or when comparing different calculation results.

```bash
cp OUTCAR OUTCAR.ref
```

--------------------------------

### Navigate to Example Directory (Bash)

Source: https://vasp.at/tutorials/latest/transition_states/part3

Navigates the terminal to the specific example directory for transition state calculations. This is a prerequisite for running subsequent commands.

```bash
cd $TUTORIALS/transition_states/e12_*

```

--------------------------------

### Download VASP Tutorials Archive

Source: https://vasp.at/tutorials/latest/index

This command downloads the latest VASP tutorials archive using curl. It's useful for offline access or when direct download links are preferred. The 'curl -O' option saves the file with its original name.

```bash
curl -O https://www.vasp.at/tutorials/latest/get_started.zip
```

--------------------------------

### Handle Missing CONTCAR for VASP Setup

Source: https://vasp.at/tutorials/latest/transition_states/part3

This script provides an alternative way to prepare the POSCAR file if the CONTCAR from a previous part is unavailable. It copies a default POSCAR.init to POSCAR, ensuring the simulation can start even without prior steps.

```bash
cd e10_*
cp POSCAR.init POSCAR
```

--------------------------------

### Display Manual Page for a Command

Source: https://vasp.at/tutorials/latest/index

This command displays the manual page for a given command (e.g., 'ls', 'cd'). It's a fundamental way to learn about command-line utilities in Linux/Unix-like systems. Press 'q' to exit the manual.

```bash
man cmd
```

--------------------------------

### Execute VASP Calculation with mpirun

Source: https://vasp.at/tutorials/latest/gw/part1

This snippet shows the command to execute the VASP calculation using mpirun on 4 processors. It assumes the necessary input files (WAVECAR, WAVEDER) are present in the directory. The command navigates to the calculation directory, copies required files, and then starts VASP.

```bash
cd $TUTORIALS/GW/e02_*
cp ../e01_*/unoccupied-states/WAVECAR ../e01_*/unoccupied-states/WAVEDER .
mpirun -np 4 vasp_std
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/bse/part1

Command to navigate to the calculation directory and run the VASP executable. This assumes VASP is installed and accessible in the system's PATH.

```bash
cd $TUTORIALS/BSE/e01_C_GW/ground-state

mpirun -np 4 vasp_std


```

--------------------------------

### Navigate to Tutorial Directory using Bash

Source: https://vasp.at/tutorials/latest/transition_states/part1

A bash command to change the current directory to the location of the VASP elbow plot tutorial. This is a standard way to access example files in a tutorial environment.

```bash
cd $TUTORIALS/transition_states/e03_*/elbow/
```

--------------------------------

### Running VASP Calculation (Bash)

Source: https://vasp.at/tutorials/latest/response/part1

This snippet shows how to execute a VASP calculation using `mpirun`. It assumes VASP is installed and accessible in the environment. The command navigates to a specific directory, copies a WAVECAR file, and then starts the VASP calculation with 2 processes.

```bash
cd $TUTORIALS/response/e01_*/electric
cp ../WAVECAR .
mpirun -np 2 vasp_std
```

```bash
cd $TUTORIALS/response/e01_*/electric-ionic
cp ../WAVECAR .
mpirun -np 2 vasp_std
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/surface/part2

This snippet shows how to navigate to the example's directory and initiate a VASP calculation using mpirun. It's a command-line operation for running simulations.

```bash
cd $TUTORIALS/surface/e06_*
mpirun -np 2 vasp_std
```

--------------------------------

### Run VASP Static Calculation

Source: https://vasp.at/tutorials/latest/phonon/part1

Navigates to the example directory and runs the VASP static calculation using mpirun. This command initiates the VASP executable to perform the static lattice energy calculation.

```bash
cd $TUTORIALS/phonon/e01_*
mpirun -np 2 vasp_std
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/gw/part1

Command to execute the VASP calculation from the terminal. This involves navigating to the calculation directory and running the VASP executable.

```bash
cd $TUTORIALS/GW/e01_*
vasp_std

```

--------------------------------

### Run VASP Calculation with vasp_gam

Source: https://vasp.at/tutorials/latest/md/part1

This snippet demonstrates how to navigate to a VASP example directory and initiate a calculation using the mpirun command with the vasp_gam executable. vasp_gam is optimized for gamma-point-only calculations, making it faster than vasp_std for such cases.

```shell
cd $TUTORIALS/MD/e01_*
mpirun -np 2 vasp_gam
```

--------------------------------

### Run VASP Calculation from Terminal

Source: https://vasp.at/tutorials/latest/hybrids/part1

This snippet shows how to navigate to a VASP example directory and initiate a standard VASP calculation from the command line. Ensure the VASP executable 'vasp_std' is in your PATH.

```shell
cd $TUTORIALS/hybrids/e01_*
vasp_std
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/hybrids/part1

This snippet shows the command to execute the VASP program for a standard calculation. It navigates to the example directory and runs 'vasp_std'.

```bash
cd $TUTORIALS/hybrids/e03_*
vasp_std
```

--------------------------------

### Setup VASP MD Simulation Environment

Source: https://vasp.at/tutorials/latest/transition_states/part3

This script sets up the VASP simulation environment by copying an initial POSCAR, linking the MLFF, and copying a specific POSCAR file. This is typically done before initiating a simulation run.

```bash
cd $TUTORIALS/transition_states/e11_*
ln -s ../mlff/MLFF_e05-12/ML_FFN ML_FF
cp $TUTORIALS/transition_states/e10_*/POSCAR.2 POSCAR

```

--------------------------------

### Run VASP Calculation and Generate Wannier90 Input

Source: https://vasp.at/tutorials/latest/gw/part1

This snippet navigates to the calculation directory, copies the WAVECAR file, and executes the VASP standard executable to perform a calculation. It then prepares for Wannier90 by copying necessary files.

```bash
cd $TUTORIALS/GW/e02_*/band-structure
cp ../WAVECAR .
vasp_std

```

--------------------------------

### Visualize Relaxed Graphene Structure with py4vasp

Source: https://vasp.at/tutorials/latest/phonon/part1

Loads a VASP calculation from a specified path and visualizes the relaxed graphene structure using py4vasp. This requires the py4vasp library to be installed.

```python
import py4vasp
mycalc = py4vasp.Calculation.from_path( "./e01_static-lattice")

mycalc.structure.plot()
```

--------------------------------

### Generate Maximally Localized Wannier Functions with Wannier90

Source: https://vasp.at/tutorials/latest/gw/part1

This command executes the Wannier90 code to construct maximally localized Wannier functions. It requires a 'wannier90.win' input file.

```bash
wannier90.x wannier90.win

```

--------------------------------

### Run VASP RPA Calculation

Source: https://vasp.at/tutorials/latest/bse/part2

This snippet shows how to execute a VASP calculation for the Random Phase Approximation (RPA) of optical absorption. It involves navigating to the example directory, copying necessary files, and running the VASP executable with mpirun.

```bash
cd $TUTORIALS/BSE/e06_LiF_RPA
cp $TUTORIALS/BSE/e04_LiF_GW/{WAVECAR,WAVEDER,W*.tmp} .
mpirun -np 4 vasp_std
```

--------------------------------

### Execute VASP Cleanup Script

Source: https://vasp.at/tutorials/latest/index

This command executes the 'vasp_rm' script, which removes specified VASP output files. It's a convenient way to clean up a directory before starting new calculations or to manage disk space.

```bash
vasp_rm
```

--------------------------------

### Run VASP Calculation

Source: https://vasp.at/tutorials/latest/surface/part1

This command navigates to the example directory and runs the VASP calculation using mpirun. Ensure VASP and MPI are installed and configured.

```bash
cd $TUTORIALS/surface/e04_*
mpirun -np 2 vasp_std
```

```bash
cd $TUTORIALS/surface/e04_*/bulk
mpirun -np 2 vasp_std
```

--------------------------------

### Set VASP Environment Variables and Download Data

Source: https://context7.com/context7/vasp_at_tutorials/llms.txt

Configures the VASP environment by setting the executable path and tutorial directory, and downloads necessary tutorial materials using curl. It then navigates to a specific tutorial directory and lists its contents to verify setup.

```bash
# Set VASP executable path
export PATH=$PATH:path/to/vasp.6.X.X/bin

# Define tutorial working directory
export TUTORIALS="path/to/tutorials/working/directory"

# Download tutorial materials
curl -O https://www.vasp.at/tutorials/latest/get_started.zip

# Navigate to tutorial directory
cd $TUTUTORIALS/molecules/e01_O-DFT

# Verify input files are present
ls
# Expected: POSCAR INCAR KPOINTS POTCAR
```

--------------------------------

### Running VASP Band Structure Calculation

Source: https://vasp.at/tutorials/latest/bulk/part1

Commands to navigate to the tutorial directory, copy the necessary charge density file (CHGCAR) from a previous calculation, and initiate the VASP calculation using mpirun.

```bash
cd $TUTORIALS/bulk/e03_*
cp ../e02_*/CHGCAR .
mpirun -np 2 vasp_std


```

--------------------------------

### Run VASP for Vibrational Analysis

Source: https://vasp.at/tutorials/latest/transition_states/part1

This snippet shows the shell commands to set up and run a VASP calculation for vibrational analysis. It involves copying the CONTCAR file, creating symbolic links, and executing VASP with mpirun. Ensure the VASP executable and necessary input files are in place.

```bash
cd $TUTORIALS/transition_states/e02_*/freq2/POSCAR
cd freq2
ln -s ../../mlff/MLFF_e02/ML_FFN ML_FF
mpirun -np 4 vasp_std
```

--------------------------------

### VASP Cleanup Script

Source: https://vasp.at/tutorials/latest/index

This bash script, named 'vasp_rm', removes common VASP output files from the current directory. It helps in cleaning up the workspace after VASP calculations. The list of files can be customized based on specific needs.

```bash
#!/bin/bash

rm -f CHG CHGCAR CONTCAR STOPCAR DOSCAR DYNMAT EIGENVAL IBZKPT OPTIC OSZICAR OUTCAR PROCAR PCDAT WAVECAR XDATCAR PARCHG vasprun.xml REPORT wannier90.win wannier90_band.gnu wannier90_band.kpt wannier90.chk wannier90.wout vaspout.h5 PENALTYPOT HILLSPOT ML_LOGFILE ML_ABN ML_FFN ML_HIS ML_REG
```

--------------------------------

### Visualize Reactant/Product Structures with Py4VASP

Source: https://vasp.at/tutorials/latest/transition_states/part1

Loads and visualizes the atomic structure from a VASP calculation directory using py4vasp. The first example visualizes the forward calculation structures, and the subsequent ones visualize the backward calculation structures.

```python
import py4vasp

struc = "./e04_IRC/p/"
calc = py4vasp.Calculation.from_path(struc) 
calc.structure.plot([1,1,1]) # visualize as a 2x2x1 supercell

```

```python
import py4vasp

struc = "./e04_IRC/m/"
calc = py4vasp.Calculation.from_path(struc) 
calc.structure.plot([1,1,1])

```

--------------------------------

### Run VASP Calculation and Copy Files

Source: https://vasp.at/tutorials/latest/bse/part1

This snippet shows how to navigate to a VASP calculation directory, copy necessary files (WAVECAR, WAVEDER, etc.) from a previous calculation, and then initiate the VASP calculation using mpirun.

```shell
cd $TUTORIALS/BSE/e02_C_BSE
cp $TUTORIALS/BSE/e01_C_GW/{WAVECAR,WAVEDER,W*.tmp} .
mpirun -np 4 vasp_std
```

--------------------------------

### Bash Script to Get Dielectric Function

Source: https://vasp.at/tutorials/latest/gw/part1

This bash script is used to generate the dielectric function data. It is a prerequisite for plotting the dielectric function using Python. No specific inputs or outputs are detailed beyond its execution.

```bash
bash get_dielectric_function.sh

```

--------------------------------

### Prepare Backward IRC Calculation Directory

Source: https://vasp.at/tutorials/latest/transition_states/part1

Sets up the directory for the backward IRC calculation. It creates a 'p' directory, copies necessary input files, creates a symbolic link to the MLFF, and runs the VASP calculation.

```bash
cd $TUTORIALS/transition_states/e04_*
mkdir p 
cp INCAR ./p/INCAR
cp POTCAR POSCAR KPOINTS ./p
cd ./p
ln -s $TUTORIALS/transition_states/mlff/MLFF_e04/ML_FFN ML_FF
mpirun -np 4 vasp_gam

```

--------------------------------

### Run VASP for Vibrational Analysis

Source: https://vasp.at/tutorials/latest/transition_states/part1

This code snippet sets up and runs a VASP calculation for vibrational analysis. It involves changing directory, linking a machine-learned force field, and executing the VASP standard calculation. Ensure the necessary environment variables and files are in place.

```bash
cd $TUTORIALS/transition_states/e02_*/freq1/
ln -s ../../mlff/MLFF_e02/ML_FFN ML_FF
mpirun -np 4 vasp_std
```

--------------------------------

### Execute VASP Calculation

Source: https://vasp.at/tutorials/latest/gw/part1

This snippet shows how to navigate to the calculation directory, copy necessary input files (WAVECAR and WAVEDER), and then execute the VASP calculation using mpirun. It assumes that 'vasp_std' is available in the system's PATH and that the environment variable '$TUTORIALS' is set.

```bash
cd $TUTORIALS/GW/e01_*/single-shot
cp ../unoccupied-states/WAVECAR ../unoccupied-states/WAVEDER .
mpirun -np 2 vasp_std
```

--------------------------------

### VASP INCAR File Setup for Relaxation

Source: https://vasp.at/tutorials/latest/bulk/part2

Configures the VASP calculation parameters for ionic relaxation and cell shape optimization. Key parameters include ISMEAR, SIGMA, ENCUT, IBRION, ISIF, NSW, and EDIFFG. This example focuses on relaxing both ionic positions and cell shape.

```text
System = cd Si

ISMEAR = 0
SIGMA  = 0.1

ENCUT  = 500

IBRION = 2
ISIF   = 3
NSW    = 5
EDIFFG = -0.001

EDIFF  = 1E-06

```

--------------------------------

### Prepare and Run VASP Calculation

Source: https://vasp.at/tutorials/latest/transition_states/part2

This snippet prepares the VASP calculation by copying necessary files and then runs the VASP executable to determine if the structure is an energetic minimum. It requires the POSCAR.pick file from a previous example and uses mpirun for parallel execution.

```bash
cd $TUTORIALS/transition_states/e09_*
ln -s $TUTORIALS/transition_states/mlff/MLFF_e05-12/ML_FFN ML_FF
cp ../e08_*/m/POSCAR.pick POSCAR

mpirun -np 4 vasp_gam
```

--------------------------------

### Run VASP IP Calculation

Source: https://vasp.at/tutorials/latest/bse/part2

This snippet demonstrates how to execute a VASP calculation for the Independent Particle (IP) approximation of optical absorption. It involves navigating to the specific example directory, copying necessary files from a previous step, and running the VASP executable using mpirun.

```bash
cd $TUTORIALS/BSE/e05_LiF_IP
cp $TUTORIALS/BSE/e04_LiF_GW/{WAVECAR,WAVEDER,W*.tmp} .
mpirun -np 4 vasp_std
```

--------------------------------

### Run G0W0 Calculation

Source: https://vasp.at/tutorials/latest/bse/part2

Executes the G0W0 calculation by copying WAVECAR and WAVEDER from the previous step and running VASP.

```bash
cd $TUTORIALS/BSE/e04_LiF_GW
cp unoccupied-states/{WAVECAR,WAVEDER} .
mpirun -np 4 vasp_std


```

--------------------------------

### VASP POSCAR File Example

Source: https://vasp.at/tutorials/latest/mlff/part1

An example of a POSCAR file for Lithium Hydride (LiH). It specifies the lattice vectors, atom types, atom counts, and direct coordinates.

```vasp
LiH
   1.0000000000000000
     7.8287847029081057    0.0184022147739740    0.0436744842177140
    -0.0000000000059867    7.8831855213703577    0.0109444497488786
    -0.0000000000095877   -0.0000000000034072    7.6332104165900363
  Li             H
              32              32
Direct
   1.9817054671128955 -0.4615590061054727 -1.4210973981086219
   1.9908342020561749 -0.4245884677547543 -1.9403613271831182
   2.0291987979331716  0.0764675410482946 -1.4473190803670182
   2.0003819712963882  0.0434600233223213 -1.9372585128028623
   1.5123565198129114 -0.4631422998001105 -1.4223489601879342
   1.5009761278969092 -0.4453976364291092 -1.9415619597553522
   1.4994078683320884  0.0453111416662948 -1.4395625528728533
   1.4920787358153047  0.0749759754227328 -1.9554193908340134
   1.4771192200171763 -0.6956853853527750 -1.1740875527008734
   1.4857876526841061 -0.6917686740837428 -1.6720984387748790
   1.4982238953402405 -0.2052814837011414 -1.2032635147179722
   1.5076711504068163 -0.1525020681581678 -1.6625242247821244
   2.0237745834200087 -0.6865011313240997 -1.1880793891256338
   1.9619016330665227 -0.6920859965869365 -1.7098418060597396
   1.9848255490801441 -0.1805732277990417 -1.1730681923310977
   1.9930394513513248 -0.1840355873006903 -1.6854182262485986
   1.2413563659888442  0.0625339636088172 -1.1946327025499690
   1.2718302311426040  0.0484902467170686 -1.6864281291080219
   1.2314950738872033 -0.4199584043288853 -1.1989048647882197
   1.2661536447359654 -0.4379143690275620 -1.6987405959330355
   1.7628840424723418  0.0709537191751443 -1.2065539892018160
   1.7525527647373844  0.0770286007123581 -1.6762495528836525
   1.7485055244828722 -0.4215982120264667 -1.1845971178647334
   1.7448584151990505 -0.4067962476727136 -1.6789000393433424
   1.2150187769175835 -0.6663000573428698 -1.9216020378849861
   1.2524959087735665 -0.6812575935175010 -1.4462894477063559
   1.2531731761067684 -0.1867855213621671 -1.9291100549777591
   1.2259867851441322 -0.1856967875773643 -1.4252590344016063
   1.7493982411143223 -0.6973680885139401 -1.9354784312219775
   1.7260537783199135 -0.7018034121966544 -1.4161537454728923
   1.7208441337659361 -0.1685614662605335 -1.9438107029069940
   1.7333301563888721 -0.1708630537252926 -1.4381194728742182
   1.2649257565892971 -0.6556014343128211 -1.1817810013660568
   1.2585150056419852 -0.6950521445902047 -1.7022316528699457
   1.2366899715948825 -0.2016212867097995 -1.1889179623891479
   1.2435972373518811 -0.1674805421763512 -1.6746199753397368
   1.7360565085394983 -0.7014677640229965 -1.1806409696057392
   1.7359989851552748 -0.7073444407917674 -1.6708498403301331
   1.7474656103131458 -0.1777402172080236 -1.1826824484643708
   1.7624647683600680 -0.1757906844274497 -1.6801347751005680
   1.2674652456927549  0.0503884660816078 -1.4356097484617691
   1.2310466249001411  0.0327844150204245 -1.9403971909709119
   1.2098635737050121 -0.4263929003423095 -1.4182292509337020
   1.2265347871913885 -0.4279538904443739 -1.9537757614594222
   1.7283483994297175  0.0558563680517394 -1.4483120337520408
   1.7756017110881346  0.0672337699055441 -1.9278288436644531
   1.7750253655838191 -0.4648904046255498 -1.4549195521056619
   1.7295923315567368 -0.4219817905587360 -1.9470964548760867   
   1.4770209675407064 -0.6938438306751112 -1.4335017836486030
   1.4723646353634945 -0.6770195558022604 -1.8958872528692552
   1.4723304891734692 -0.2127593172465675 -1.4473881729001288
   1.4891149694386838 -0.1626854203039640 -1.9603811580254049
   1.9926313874455659 -0.6908264960781072 -1.4497987024242049
   1.9867827816577046 -0.6980021465438837 -1.9437561167974060
   1.9931966385787605 -0.1915982553314239 -1.4347752030340506
   1.9783410196089279 -0.1914865493283802 -1.9326203981603027
   1.4764840292260042 -0.4461711698868597 -1.1775341299154893
   1.4875834918595106 -0.4154993260957937 -1.6775044859519459
   1.4810701055683364  0.0320617038904891 -1.2116883860657408
   1.5095460900056492  0.0791435657918060 -1.6881031427292668
   1.9825393542246055 -0.4577940687402631 -1.1998173435832227
   1.9904498339985650 -0.4649735127116422 -1.6891634696973543
   2.0269030501276393  0.0453801235753682 -1.1771020717088660
   1.9888483400537196  0.0679206981683836 -1.6933672606587671
```

--------------------------------

### VASP POTCAR Example for Carbon

Source: https://vasp.at/tutorials/latest/phonon/part1

An example of a POTCAR file entry for a Carbon atom, specifying the pseudopotential type (PAW C_s) and version. This file is essential for VASP calculations as it contains the pseudopotentials for each element.

```text
PAW C_s 04May1998  
4.00000000000000
```

--------------------------------

### Navigate to Calculation Directory

Source: https://vasp.at/tutorials/latest/bse/part1

Changes the current directory to the specified VASP tutorial directory for BSE calculations.

```bash
cd $TUTORIALS/BSE/e03_C_TDHF/

```

--------------------------------

### POSCAR Structure File (Example 2)

Source: https://vasp.at/tutorials/latest/transition_states/part1

Defines the atomic structure, including lattice vectors, atom types, and counts. This example uses Cartesian coordinates without selective dynamics.

```text
Si
 1.0000000000000000
     5.4699999999999998    5.4699999999999998    0.0000000000000000
     0.0000000000000000    5.4699999999999998    5.4699999999999998
     5.4699999999999998    0.0000000000000000    5.4699999999999998
 Si
  15
Cartesian
  0.0000000000000000  0.0000000000000000  0.0000000000000000
  1.3665156210224796  1.3665156210224796  1.3665156210224796
  2.7324848450114785  0.0000000000000000  2.7324848450114785
  4.0997621072327810  1.3632312112164302  4.0997621072327810
  0.0000000000000000  2.7324848450114785  2.7324848450114785
  1.3632312112164302  4.0997621072327810  4.0997621072327810
  2.7311343338126961  2.7311343338126961  5.4622686676253922
  4.1075261937953860  4.1075261937953860  6.8246256435873960
  2.7324848450114785  2.7324848450114785  0.0000000000000000
  4.0997621072327810  4.0997621072327810  1.3632312112164302
  5.4622686676253922  2.7311343338126961  2.7311343338126961
  6.8246256435873960  4.1075261937953860  4.1075261937953860
  2.7311343338126961  5.4622686676253922  2.7311343338126961
  4.1075261937953860  6.8246256435873960  4.1075261937953860
  6.8280528709476682  6.8280528709476682  6.8280528709476682
```

--------------------------------

### KPOINTS File Example for Gamma-point Calculation

Source: https://vasp.at/tutorials/latest/molecules/part2

Defines the k-point mesh for the electronic self-consistent field (SCF) calculation. This example uses a Gamma-point only (1x1x1) Monkhorst-Pack grid, suitable for small systems or initial tests.

```KPOINTS
Gamma-point only
 0
Monkhorst Pack
 1 1 1
 0 0 0

```

--------------------------------

### Prepare VASP Transition State Calculation Directory

Source: https://vasp.at/tutorials/latest/transition_states/part2

This snippet prepares the directory for a VASP transition state calculation by copying a relaxed structure, creating a symbolic link to a machine learning force field, and setting up the POSCAR file.

```bash
cd $TUTORIALS/transition_states/e07_*
ln -s $TUTORIALS/transition_states/mlff/MLFF_e05-12/ML_FFN ML_FF
cp ../e06_*/CONTCAR POSCAR
```

--------------------------------

### Prepare Forward IRC Calculation Directory

Source: https://vasp.at/tutorials/latest/transition_states/part1

Sets up the directory for the forward IRC calculation. It creates an 'm' directory, copies input files, modifies the INCAR to set the IRC direction to 1, links the MLFF, and runs VASP.

```bash
cd $TUTORIALS/transition_states/e04_*
mkdir m
cp INCAR ./m/INCAR
cp POTCAR POSCAR KPOINTS ./m
cd ./m
sed -i 's/IRC_DIRECTION = -1/IRC_DIRECTION = 1/g' INCAR
ln -s $TUTORIALS/transition_states/mlff/MLFF_e04/ML_FFN ML_FF
mpirun -np 4 vasp_gam

```

--------------------------------

### POSCAR Structure File (Example 1)

Source: https://vasp.at/tutorials/latest/transition_states/part1

Defines the atomic structure, including lattice vectors, atom types, counts, and selective dynamics information. This example uses Cartesian coordinates and selective dynamics.

```text
Si
 1.0000000000000000
     5.4699999999999998    5.4699999999999998    0.0000000000000000
     0.0000000000000000    5.4699999999999998    5.4699999999999998
     5.4699999999999998    0.0000000000000000    5.4699999999999998
 Si
  15
Selective Dynamics
Cartesian
  0.0000000000000000  0.0000000000000000  0.0000000000000000 F F F
  1.3666442271977317  1.3666442271977317  1.3666442271977317 T T T
  2.7329769561430752  0.0000000000000000  2.7329769561430752 T F T
  4.1003993688426394  1.3635567553287469  4.1003993688426394 T T T
  0.0000000000000000  2.7329769561430752  2.7329769561430752 F T T
  1.3635567553287469  4.1003993688426394  4.1003993688426394 T T T
  2.7325583452738460  2.7325583452738460  5.4651166905476920 T T T
  4.1082710101368924  4.1082710101368924  6.8282275234341077 T T T
  2.7329769561430752  2.7329769561430752  0.0000000000000000 T T F
  4.1003993688426394  4.1003993688426394  1.3635567553287469 T T T
  5.4651166905476920  2.7325583452738460  2.7325583452738460 T T T
  6.8282275234341077  4.1082710101368924  4.1082710101368924 T T T
  2.7325583452738460  5.4651166905476920  2.7325583452738460 T T T
  4.1082710101368924  6.8282275234341077  4.1082710101368924 T T T
  6.5617843246528968  6.5617843246528968  6.5617843246528968 T T T
```

--------------------------------

### VASP Calculation Execution

Source: https://vasp.at/tutorials/latest/bse/part2

This snippet shows the commands to execute a VASP calculation. It involves navigating to the calculation directory, copying necessary WAVECAR files, and running the VASP executable using MPI.

```bash
cd $TUTORIALS/BSE/e07_LiF_BSE
cp $TUTORIALS/BSE/e04_LiF_GW/{WAVECAR,WAVEDER,W*.tmp} .
mpirun -np 4 vasp_std


```

--------------------------------

### VASP POTCAR: Si_GW Potential for GW Calculations

Source: https://vasp.at/tutorials/latest/gw/part1

Shows an example of a POTCAR file for Silicon specifically prepared for GW calculations. These potentials are designed to accurately reproduce atomic scattering properties over a wider energy range, essential for computing unoccupied states.

```text
  PAW_PBE Si_GW 04May2012                    
   4.00000000000000     
 parameters from PSCTR are:
   VRHFIN =Si: s2p2
   LEXCH  = PE
   EATOM  =   103.0669 eV,    7.5752 Ry

   TITEL  = PAW_PBE Si_GW 04May2012
   LULTRA =        F    use ultrasoft PP ?
   ...
   ...

```

--------------------------------

### VASP POSCAR with Selective Dynamics (Alternative Example)

Source: https://vasp.at/tutorials/latest/transition_states/part1

This snippet shows another example of a VASP POSCAR file with 'Selective Dynamics'. It demonstrates the flexibility in controlling atomic movements during simulations by specifying 'T' or 'F' for each Cartesian coordinate, allowing fine-grained control over the relaxation process.

```text
Si
 1.0000000000000000
     5.4699999999999998    5.4699999999999998    0.0000000000000000
     0.0000000000000000    5.4699999999999998    5.4699999999999998
     5.4699999999999998    0.0000000000000000    5.4699999999999998
 Si
  15
Selective Dynamics
Cartesian
  0.0000000000000000  0.0000000000000000  0.0000000000000000 F F F
  1.3669014395482357  1.3669014395482357  1.3669014395482357 T T T
  2.7339611784062692  0.0000000000000000  2.7339611784062692 T F T
  4.1016738920623554  1.3642078435533804  4.1016738920623554 T T T
  0.0000000000000000  2.7339611784062692  2.7339611784062692 F T T
  1.3642078435533804  4.1016738920623554  4.1016738920623554 T T T
  2.7354063681961454  2.7354063681961454  5.4708127363922907 T T T
  4.1097606428199054  4.1097606428199054  6.8354312831275301 T T T
  2.7339611784062692  2.7339611784062692  0.0000000000000000 T T F
  4.1016738920623554  4.1016738920623554  1.3642078435533804 T T T
  5.4708127363922907  2.7354063681961454  2.7354063681961454 T T T
  6.8354312831275301  4.1097606428199045  4.1097606428199054 T T T
  2.7354063681961454  5.4708127363922907  2.7354063681961454 T T T
  4.1097606428199045  6.8354312831275301  4.1097606428199045 T T T
  6.0292472320633550  6.0292472320633550  6.0292472320633550 T T T
```

--------------------------------

### VASP POSCAR with Selective Dynamics (Third Example)

Source: https://vasp.at/tutorials/latest/transition_states/part1

This snippet presents a third example of a VASP POSCAR file configured with 'Selective Dynamics'. It showcases how to precisely control atomic freedom in simulations by using boolean flags for each atomic coordinate, enabling targeted relaxation or fixation of atoms.

```text
Si
 1.0000000000000000
     5.4699999999999998    5.4699999999999998    0.0000000000000000
     0.0000000000000000    5.4699999999999998    5.4699999999999998
     5.4699999999999998    0.0000000000000000    5.4699999999999998
 Si
  15
Selective Dynamics
Cartesian
  0.0000000000000000  0.0000000000000000  0.0000000000000000 F F F
  1.3667728333729838  1.3667728333729838  1.3667728333729838 T T T
  2.7334690672746720  0.0000000000000000  2.7334690672746720 T F T
  4.1010366304524979  1.3638822994410638  4.1010366304524979 T T T
  0.0000000000000000  2.7334690672746720  2.7334690672746720 F T T
  1.3638822994410638  4.1010366304524979  4.1010366304524979 T T T
  2.7339823567349955  2.7339823567349955  5.4679647134699909 T T T
  4.1090158264783989  4.1090158264783989  6.8318294032808193 T T T
  2.7334690672746720  2.7334690672746720  0.0000000000000000 T T F
```

--------------------------------

### Create VASP Supercells with pymatgen (Python)

Source: https://vasp.at/tutorials/latest/phonon/part2

Generates supercells for VASP simulations by manipulating crystal structures. This code uses the pymatgen library to read an existing POSCAR file, create a supercell of a specified size (e.g., 2x2x2), and write the new structure to a POSCAR file. Ensure pymatgen is installed (`pip install pymatgen`) and the input POSCAR file exists.

```python
from pymatgen.core import Structure
from pymatgen.io.vasp import Poscar

my_struc = Structure.from_file("./e05_mgo-fin-diff-force-constants/POSCAR")

# make a 2x2x2 supercell
my_struc.make_supercell([2,2,2])

# write supercell to POSCAR format with specified filename
folder = "./e05_mgo-fin-diff-force-constants/supercell_2x2x2"
Poscar(my_struc).write_file(filename=f"{folder}/POSCAR",significant_figures=16)
```

--------------------------------

### Graphene POTCAR File

Source: https://vasp.at/tutorials/latest/phonon/part1

Specifies the pseudopotential to be used for carbon atoms in the VASP calculation. This example uses the PAW C_s pseudopotential from 04May1998.

```vasp
PAW C_s 04May1998

```

--------------------------------

### Execute VASP for Unoccupied States Calculation

Source: https://vasp.at/tutorials/latest/bse/part1

Navigates to the directory for unoccupied states calculation, copies the WAVECAR from the ground state, and runs the VASP calculation using mpirun. Ensure the VASP executable and MPI environment are correctly set up.

```bash
cd $TUTORIALS/BSE/e01_C_GW/unoccupied-states
cp ../ground-state/WAVECAR .
mpirun -np 4 vasp_std
```

--------------------------------

### ICONST: Ionic Constraints

Source: https://vasp.at/tutorials/latest/transition_states/part3

Defines constraints on ionic positions during the simulation. This example shows constraints for specific atoms (R for restricted, S for fixed).

```vasp-iconst
R 3 25 0
R 3 2 0
S -1 1 7

```
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