Q-Chem 4.3 User’s Manual

2.5 User Account Adjustments

In order for individual users to run Q-Chem, User file access permissions must be set correctly so that the user can read, write and execute the necessary Q-Chem files. It may be advantageous to create a qchem user group on your machine and recursively change the group ownership of the Q-Chem directory to qchem group.

The Q-Chem runtime environment need to be initiated prior to running any Q-Chem calculations, which is done by sourcing the environment setup script qcenv.sh [for bash] or qcenv.csh [for tcsh/csh] placed in your Q-Chem top directory after a successful installation. It might be more convenient for user to include the Q-Chem environment setup in their shell startup script, e.g., .cshrc/.tcshrc for csh/tcsh or .bashrc for bash.

For users using the csh shell (or equivalent), add the following lines to their home directory .cshrc file:

setenv  QC         qchem_root_directory_name
setenv  QCSCRATCH  scratch_directory_name
source  $QC/qcenv.csh

For users using the Bourne-again shell (bash), add the following lines to their home directory .bashrc file:

export QC=qchem_root_directory_name
export QCSCRATCH=scratch_directory_name
. $QC/qcenv.sh