Theoretical study of the structure and vibrational spectra of VO2X2- (X = F, Cl, Br, I) anions

We have carried out a structural and vibrational theoretical study for the four members of the series VO2X2 (X = F, Cl, Br, 1). In order to assess the behaviour of such theoretical calculations (ab initio and DFT) we have made a comparative work for the fluorine and chlorine derivatives, for which vibrational data exist, to evaluate not only the best level of theory but also the best basis set to be used to reproduce the experimental wavenumbers. The results were then used to predict the vibrational spectra and molecular geometry of the other members of the series, for which there are no experimental data. The theoretical vibrational calculations allowed us to obtain a set of scaled force constants fitting the observed wavenumbers. (C) 2003 Elsevier Science B.V. All rights reserved.