Systematic study of the performance of density functional theory methods for prediction of energies and geometries of organoselenium compounds.

A variety of density functional theory (DFT) methods are paired with Pople basis sets of varying sizes and evaluated for use with organoselenium compounds. The ability of each method to predict reliable geometries and energies is determined through comparison with quadratic configuration interaction with single and double excitations (QCISD) results. The recommended procedure for accurate prediction of energies and geometries is to use the B3PW91 functional with the 6-311G(2df,p) basis set. The B3PW91/6-31G(d,p) level of theory gives almost identical geometries as larger basis sets, so geometries can be predicted at this level for computational efficiency.