From: Ern Ong (
Date: Mon Jan 22 2018 - 02:14:54 CST

Hi VMD users,

The input of a spin multiplicity value is required in Opt. Geometry, Water Int. and Scan Torsions. Regarding to the determination of a correct spin multiplicity value, where M = 2S + 1, there are several people suggested that as a rule of thumb, different values of spin multiplicity should be run (may be from 1 to 7) and select the one that provides the lowest value of nuclear repulsion energy (in Hartrees) as reported in the Gaussian output file.

Can someone please comment on this convention?

Thank you.

Best Regards,

Ernest Ong Ern Seang

PhD student
School of Engineering and Information Technology (SEIT)
University of New South Wales@ ADFA
NorthCott Drive, Campbell
ACT 2600, Australia.