| 11:00:58 AM PDT - Tue, Aug 27th 2013 |
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Hi,
I'm a new NWchem user trying to run a decently large QM/MM simulation. My QM region consists of ~150 atoms, and my MM region will be ~500 ethanol molecules. I'd like to apply this procedure to larger systems in the future, so I figured I would use the QM/MM capabilities in the PSPW module. The documentation has a very instructive example (http://nwchemgit.github.io/images/Ccl4-64water.nw), however I'm a bit confused about how to translate this procedure to my molecule.
More specifically, I've no idea where the Lennard-Jones ion parameters came from, and thus I've no clue where to obtain the relevant values for my molecule. Additionally, it's unclear to me if two carbon atoms in different chemical environments would have different LJ parameters, or if the LJ parameters of atoms in the QM region change as a function of solvent molecules in the MM region.
I'm aware of the more standard QM/MM Gaussian-based module and am working to get that going for my systems, too, but any help with the PSPW module and these ion parameters would be greatly appreciated.
Thanks!
Sam
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