AB-INITIO AND DENSITY-FUNCTIONAL STUDY OF THE JAHN-TELLER DISTORTION IN THE SILANE RADICAL-CATION

An ab initio and density functional study is made of the Jahn-Teller d istortion of the silane radical cation using Dunning's cc-pVTZ basis s et. For this cation, the D-2d, C-3v, C-2v and C-s structures are fully optimized and analyzed using an energy component analysis. The distor tion towards the lowest energy geometry results in an increase in kine tic energy and a decrease in the electron-nuclear attraction energy, e lectron-electron repulsion energy and nuclear-nuclear repulsion. The e xact exchange density functional methods B3LYP and B3PW91 turn out to be the methods best suited for the study of geometries, energies and v ibrational spectra of these cations.