Optimizations with multiple negative frequencies

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8:37:58 AM PDT - Thu, Apr 18th 2013
I am optimizing transition states in NWChem under solvated conditions, and the optimization results in multiple negative frequencies, indicating that the lowest energy transition state was not necessarily found. I know in GAussian there's a keyword "noeigen", or something like that, which finds the largest negative frequency of all the negative frequencies, and keeps optimizing the transition state geometry until the largest negative frequency is the only negative frequency calculated. Is there some similar aspect and key word that can be used in NWChem?

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4:33:02 PM PDT - Fri, Apr 19th 2013
We do not have the same system in place. However, you can do this in two ways: 1. After the geometry optimization the displacements of the imaginary normal modes are printed. You an simply use this as a starting point for a next geometry optimization. 2. You can try and follow the negative mode to a potential saddle point and minimize from there (see http://nwchemgit.github.io/index.php/Release61:Geometry_Optimization for details).