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 #