How to run Q-Chem on USC HPCC

First, you need to secure an allocation on HPCC. Check if your group already has an allocation and ask your professor to add you to the list of users. If you do not have one --- request HPC account and allocation (this should be done by the PI). If you are enrolled in Chem545, your name will be added to the class HPCC user list. Once you have the allocation, email to and request to be added to the qchem group. Once this is done, you can submit jobs either by using IQmol graphic interface (which you need to install on your laptop or desktop) or by ssh-ing to HPCC and using a PBS script (this requires a basic knowledge of Unix OS).

Using IQmol

  • Download IQmol graphic interface from the IQmol website.
  • Follow the steps in this tutorial to configure IQmol to submit jobs to HPCC.

From HPCC command-line using PBS

  • Login to USC HPCC using your USC/HPC account.
  • Create your Q-Chem input file:
  • Create PBS run script
    with the following content making necessary adjustments to queue, walltime, etc.
    #PBS -q default
    #PBS -l walltime=00:30:00
    #PBS -l ncpus=1
    export QC=/usr/usc/qchem/default
    export QCAUX=$QC/qcaux
    export QCPLATFORM=LINUX_Ix86_64
    export QCRSH=ssh
    export PATH=$QC/bin:$PATH
    qchem -nt 1 my_input.inp my_output.out
  • Submit your PBS job:
  • To run QChem in parallel add
    -nt N
    to the qchem command (N is the number of CPU cores). Consult QChem manual for more information.

Additional Resources