MP2 frequencies

[anthony.scott |-at-| anu.edu.au (Anthony P Scott)]

 I have mailed Errol directly with this reply but since at least one other
 fellow computational chemist is not aware of our recent paper dealing
 withsubject I thought I might as well blow my own trumpet.
 A paper dealing with the scaling factors that should be used when applied to
 MP2-full/6-31g* harmonic vibrational frequencies appeared in Israel J. Chem.
 1993, 33, 345. A scale factor of 0.9427 for frequencies and 0.9646 for
 zero-point energies was derived for the MP2 method. This compares to values
 of 0.8929 and 0.9135 respectively for HF/6-31G*.
 Work has also been carried out here on deriving appropriate scale factors
 for HF/6-311g**, HF/6-311G(df,p), MP2-fc/6-31G*, MP2-fc/6-311G**, BLYP/6-31G*,
 BLYP/6-311G(df,p) methods.
 Of current interest in the context of the original question is the scale
 factors for MP2-fc/6-31g*. They have been determined to be 0.9434 cm-1 with
 a RMS error slightly above that for the MP2-full results.
 If there is enough interest in these results I might be able to post a
 complete summary of them.
 I hope this information is of some use.
 Kind Regards,
 Anthony P. Scott
 Research Officer
 Computational Chemistry Group
 Research School of Chemistry
 Australian National University
 Canberra, ACT, Australia.