A NEW WAY OF ANALYZING VIBRATIONAL-SPECTRA - IV - APPLICATION AND TESTING OF ADIABATIC MODES WITHIN THE CONCEPT OF THE CHARACTERIZATION OF NORMAL-MODES

Citation
Z. Konkoli et al., A NEW WAY OF ANALYZING VIBRATIONAL-SPECTRA - IV - APPLICATION AND TESTING OF ADIABATIC MODES WITHIN THE CONCEPT OF THE CHARACTERIZATION OF NORMAL-MODES, International journal of quantum chemistry, 67(1), 1998, pp. 41-55
Citations number
17
Categorie Soggetti
Chemistry Physical
ISSN journal
00207608
Volume
67
Issue
1
Year of publication
1998
Pages
41 - 55
Database
ISI
SICI code
0020-7608(1998)67:1<41:ANWOAV>2.0.ZU;2-2
Abstract
The CNM (characterization of normal modes) method for extracting chemi cal information out of vibrational spectra is tested for vibrational s pectra of molecules with relatively strong or relatively weak coupling between internal vibrational modes. Symmetry, parameter set stability , and frequency uncertainty tests are applied to check whether interna l vibrational modes. internal mode frequencies, and amplitudes A(n mu) comply with symmetry, are independent of the set of internal paramete rs zeta(n) used to describe molecular geometry or fulfill a Lorentzian correlation between amplitudes A(n mu) and frequency differences Delt a omega(n mu) = omega(n) - omega(mu). In all cases considered, amplitu des A(n mu) based on adiabatic internal modes and mass or force consta nt matrices as metric Omicron are superior to any other definition of amplitude. They represent the basic elements of the new CNM method tha t leads to chemically reasonable results and presents a new way of ext racting chemical information oat of vibrational spectra. A number of d eficiencies of the potential energy distribution (FED) analysis is dis cussed. (C) 1998 John Wiley & Sons, Inc. Int J.