xTB and CREST - BNNLab/BN_Group_Wiki GitHub Wiki

1. Installing and using xTB and CREST

Installation:

  1. Download the latest version (.tar.xz) from here. For CREST download from here.

  2. Extract the tar file to the home directory, rename to xtb and add CREST to the /bin/ folder.

  3. Add xtb to the program path by adding the following to .bashrc:

XTBHOME=$HOME/xtb 

XTBPATH=${ XTBHOME} /share/xtb:${ HOME}  

MANPATH=${ MANPATH} :${ HOME} /share/man 

PATH=${ PATH} :${ XTBHOME} /bin 

PKG_CONFIG_PATH=${ PKG_CONFIG_PATH} :${ XTBHOME} /share/xtb 

export PATH XTBPATH MANPATH PKG_CONFIG_PATH 

export OMP_STACKSIZE=1G 
ulimit -s unlimited
  1. The programs can now be called from the command line with xtb and crest.

2. Using xTB:

Geometry opt: 

xtb "xyzfile.xyz" --opt

Frequency:

xtb "xyzfile.xyz" --hess

Charge and spin:

xtb "xyzfile.xyz" --chrg 1 --uhf 0 --opt # +1 charge and total spin of 0 NOT spin multiplicity

For more details commands see here.

3. Using CREST:

Multi-threading in CREST

chmod +x /users/cmsma/crest/crest
export PATH=$PATH:/users/cmsma/crest/

export OMP_NUM_THREADS=16

crest mol1.xyz > mol1.out -T 16 --chrg 0

Conformer-Rotamer search:

crest "xyzfile.xyz" # Uses the default iMTD-GC algorithm with GFN2-xTB

Charge and spin:

crest "xyzfile.xyz" -chrg 1 -uhf 0 # Charge of +1 and spin of 0

For more detailed inputs see here.

4. Using xTB with ORCA:

  1. Ensure xTB is in your $PATH

  2. Navigate to your ORCA installation directory

  3. In the console type ln -s $(which xtb) otool_xtb to link the xtb executable to ORCA.

  4. xTB can now be used in ORCA using the XTB keyword

5. Using xTB on ARC4

xTB and CREST can be used on ARC if set up in your home folder. Installation is the same process as described above in your home directory on ARC.

xTB can also be used through ORCA on ARC4 and must be setup separately. After installing xTB, ORCA must be setup with symbolic links in your home directory to be able to access xTB.

  1. Create a folder named orca in your home directory.

  2. cd into the created folder and run the following command to create a symbolic link between the ORCA install directory and your home directory,

for i in /apps/applications/orca/4.2.1/1/default/bin/*; do ln -s $i; done

  1. Add the new ORCA path to your .bashrc file. (you may have to ensure hidden files are viewable)

export PATH=$HOME/orca:$PATH

  1. Link xTB to the newly created ORCA directory. (Same as above.)

ln -s $(which xtb) otool_xtb

  1. You should now be able to run xTB inside ORCA by calling the full path

/home/homeXX/username/orca/orca "input_file.inp" > "output_file.out"