Skip to content



NWChem aims to provide its users with computational chemistry tools that are scalable both in their ability to treat large scientific computational chemistry problems efficiently, and in their use of available parallel computing resources from high-performance parallel supercomputers to conventional workstation clusters.

Installed Versions

For a current list of installed versions, execute:

$ ml av NWChem


NWChem is compiled for parallel MPI execution. Normal procedure for MPI jobs applies. Sample jobscript (for Salomon on 24 threads):

#PBS -A IT4I-0-0
#PBS -q qprod
#PBS -l select=1:ncpus=24:mpiprocs=24

module add NWChem
mpirun nwchem h2o.nw


Refer to the documentation and in the input file set the following directives:

  • MEMORY : controls the amount of memory NWChem will use
  • SCRATCH_DIR : set this to a directory in SCRATCH filesystem - Salomon (or run the calculation completely in a scratch directory). For certain calculations, it might be advisable to reduce I/O by forcing "direct" mode, eg. "scf direct"