The prediction of vibrational frequencies of inorganic molecules using density functional theory

Vibrational frequencies for 50 inorganic molecules (511 frequencies) have been calculated using the S-VWN (LSDA), B-LYP and B3-LYP functionals in conjunction with either the 6-311G* basis set or the LANL2DZ effective core potential (ECP). All methods yielded reasonable agreement with experiment, with overall root mean square errors from the 6-311G* calculations (38–39 cm−1) being slightly smaller than the LANL2DZ results (44–47 cm−1). Results obtained using the 6-31G* basis set suggest that the larger RMS values obtained for the LANL2DZ calculations can be attributed to the ECP appproximation.