Abstract: MATH/CHEM/COMP 2002, Dubrovnik, June 24-29, 2002

Influence of Density Functional on Vibrational Dynamics

Zlatko Meic¹, Tomica Hrenar¹, and Roland Mitric²

¹Faculty of Science, University of Zagreb, Strossmayerov trg 14, HR-10000 Zagreb, Croatia

²Humboldt Universitaet zu Berlin, Institut fuer Chemie, Brook-Taylor-Str. 2 12489 Berlin

An accurate prediction of vibrational spectra is one of the most demanding tests for potential energy surface, which is also a test for the used electronic structure method of the calculation. In this study, two electron correlation functionals, namely B3LYP and B3PW91, were tested by performing calculations of vibrational wavenumbers and vibrational dynamics for a set of structurally related molecules: benzaldehyde (BA), trans‑stilbene (tSB) and salicylideneaniline (SAN). Different basis sets, i.e. 6-31G* and 6‑311+G**, were used.

Influence of chosen functionals and quality of basis sets on the obtained results will be presented and discussed. Vibrational patterns of some characteristic modes will be compared with experimental results.

The assumption of the presence of a number of different conformations is confirmed by performing relaxed potential energy scan.