Scaling procedures are known to reproduce very accurate vibrational spectra provided that multiparameter scaling in conjunction with high-quality force fields is carried out. In contrast to purely theoretical approaches (variational and perturbational), they are applicable to large systems. In this work, a brief review of the scaling procedures is given. The emphasis is put on the recently proposed effective scaling frequency factor (ESFF) method [Chem. Phys. Lett., <bold>446</bold>, 191, (2007), J. Mol. Spectr., <bold>264</bold>, 66, (2010)] - the multiparameter frequency scaling method providing better scaled frequencies than the well-established scaled quantum mechanical (SQM) force field approach. In addition, the results of our calculations on the benzene-based related systems, i.e., benzene and most of its methyl derivatives, are presented. The calculations concern the middle- and low-frequency range of the vibrational spectra, where strong mixing of the local vibrations often takes place. The factors transferability problem is discussed.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.