There is only one file type that uses the .NWO extension:
NWChem Output File
Chemical file created by NWChem, a computational chemistry software package; contains output data from a NWChem simulation, such as the electric density of orbitals in a molecule.
The NWChem software is meant to be run on high-performance supercomputers or workstation clusters. The software was developed by a group in the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory.
Updated: July 27, 2014