Electronic spectra of some post-transition-metal halide complexes

Abstract

The electronic absorption spectra of tetrahalide complexes of Zn^II, Cd^II, Hg^II, and Tl^III have been measured either in solution or as thin films. The effects of second-order spin–orbit coupling account satisfactorily for the observed band intensities and splittings. The one-electron transitions responsible for the lowest-energy groups of absorption bands are all of the type t₂→a₁. There is no evidence for transitions from the non-bonding t₁ or e molecular orbitals, and an explanation is advanced for their non-appearance.