GAMESS-US is a program for ab initio molecular quantum chemistry. Briefly, GAMESS-US can compute SCF wavefunctions ranging from RHF, ROHF, UHF, GVB, and MCSCF. Correlation corrections to these SCF wavefunctions include Configuration Interaction, second order perturbation Theory, and Coupled-Cluster approaches, as well as the Density Functional Theory approximation. Excited states can be computed by CI, EOM, or TD-DFT procedures. Nuclear gradients are available, for automatic geometry optimization, transition state searches, or reaction path following. Computation of the energy hessian permits prediction of vibrational frequencies, with IR or Raman intensities. Solvent effects may be modeled by the discrete Effective Fragment potentials, or continuum models such as the Polarizable Continuum Model. Numerous relativistic computations are available, including infinite order two component scalar corrections, with various spin-orbit coupling options. The Fragment Molecular Orbital method permits use of many of these sophisticated treatments to be used on very large systems, by dividing the computation into small fragments. Nuclear wavefunctions can also be computed, in VSCF, or with explicit treatment of nuclear orbitals by the NEO code.
We will compile, test functionality and provide the most recent version of GAMESS-US on regularly on a “best effort” basis, that is as soon as we can manage. Each version gets its own subdirectory and module. Old versions do not get removed, but a warning message may be added to versions having serious problems. Please report any such problems you find.
Load the GAMESS-US module corresponding to the version you want to use. For instance
module load gamess/01may12r1
Then run the launcher script, giving the input file as the first (and only) argument and redirect the output to desired output file.
gamess.run inputfile.inp > outputfile.out
If you want your run to use a specific number of CPU cores, you may add the desired number as a second argument to the runscript after the input file, e.g.
gamess.run inputfile.inp 1 > outputfile.out
This requests a single core to run on, useful for the non-parallelised parts of GAMESS-US.
A minimum batch script for running GAMESS-US looks like this:
#!/bin/bash #SBATCH -N 4 #SBATCH -t 4:00:00 #SBATCH -J jobname #SBATCH --exclusive #SBATCH -A SNIC-xxx-yyy module load gamess/01may12r1 WD=$PWD # Uncomment/edit this if you don't want restart/traj/punch data. Please put # this somewhere under /nobackup #export USERSCR=/some/path/to/personal/scr/dir # default is $PWD/scr gamess.run inputfile.inp > outputfile.log # This example assumes you submit # this script from your working directory # Optionally you may want to run on a specific number of cores. For one (1) # core this is accomplished with: # gamess.run inputfile.inp 1 > outputfile.log
(Note that you should edit the jobname, account number, number of nodes and requested walltime before submitting.)
Running your GAMESS-US calculation in this manner will make use of all CPU cores accessible within your job. In the above example running on Triolith 4 * 16 CPU cores would be used an because of a peculiarity in GAMESS-US’s mprgramming, twice the number of MPI ranks.