Freq calculation with freeze atoms

4:17:07 AM PDT - Fri, May 13th 2011
Hello! I have a question regarding to the vibrational frequencies calculations. Is it posible in NWchem (and with RI-MP2 methofology) to compute the vibrational frequencies of only a selected set of atoms of a system. (For instance to compute only the vibrational modes associated to an adsorbed molecule). I know that it is possible to do a constrained optimization over a selected group of atoms with the SET variable: set geometry:actlist atom1 atom2... atomx is there something similar for thre freqs? Thanks in advance...

Forum Vet

11:54:14 AM PDT - Tue, May 17th 2011
Hi, No, there is not such an option. You probably could uncouple the vibrational modes of subsets of the system (though I don't think it would give you very realistic modes), but we do not have this capability in NWChem. Bert Quote: May 13th 11:17 am Hello! I have a question regarding to the vibrational frequencies calculations. Is it posible in NWchem (and with RI-MP2 methofology) to compute the vibrational frequencies of only a selected set of atoms of a system. (For instance to compute only the vibrational modes associated to an adsorbed molecule). I know that it is possible to do a constrained optimization over a selected group of atoms with the SET variable: set geometry:actlist atom1 atom2... atomx is there something similar for thre freqs? Thanks in advance...