CCL: scaling factor in frequency calculation

 Sent to CCL by: "Maxim L. Kuznetsov" [max]~[mail.ist.utl.pt]
 Dear Partha,
 In principle, for the careful theoretical analysis of vibrational spectra, it is
 better to introduce the scale factors for force constants rather than for
 frequencies. The scale factors for each group of force constants may be
 different. See [J. Mol. Struct. THEOCHEM, 1998, 453, 17-28] as example.
 Best regards
 M. Kuznetsov
 > Dear All,
 > I am trying to see the effect of Cu2+ binding on a ligand by Raman
 > spectroscopy and trying to match those results with DFT. For the ligand, I
 > got a very good match with the experimental spectrum after applying a
 scaling
 > factor. However for the complex if I use the same scaling factor, I see
 some
 > modes in the 1500-1700 cm-1 regions are underestimated. If I do not use any
 > scaling factor in that the match is better. I am using lanl2dz ECP and
 basis
 > set combination for Cu. Is it okay to use dual scaling (0.961 for 1000-1500
 > and 1 for the 1500-1700 region) for matching the experimental data. Then I
 > can not directly compare my theoretical results with the experiment. Any
 > suggestion would be of great help.
 > Partha