Ab initio calculation of geometry and vibrational frequencies of the isovalence-electronic tetrahedral species XCl 4ε and YBr 4ε {X = K, Ca, Ga-Kr; Y = Ne-Ca, Ga-Kr}

Abstract

Geometry, vibrational frequencies and IR intensities are calculated for the title species with split valence and minimal basis sets, and with split valence only basis with ECPs, all augmented with polarization functions. With a few apparent exceptions the split valence values give a good fit to experimental frequencies, with a roughly constant deviation that is easily corrected with a simple scaling. From comparing the ratios between experimental and calculated frequencies for isoelectronic series, scaled quantum mechanical frequencies are predicted for six species for which no reliable observation of frequencies are reported.