Role of the Trigonal t2e2-nen Single-Ion Configuration in d3d3Metal-Metal σ-Bonded Dimers

Abstract

The theory of the trigonal t2e2-nen single-ion and (t2e2-nen)a(t2e2-nen) pair configurations is presented in which account is taken of the single-ion electron repulsion, cubic and trigonal ligand Fields, Zeeman splitting, and the M-M π interaction of the pair. Application of the theory to the electronic spectra of M02X93−(X = Cl, Br) species offers a viable explanation for the broad spin-allowed bands observed above 16000 cm−1in terms of singly excited pair states involving the trigonal t2e→ e orbital transition. Furthermore, the anomalously low orbital g values reported previously for the lower lying pair multiplets in the chloro complex1can be explained by extensive mixing of the single-ion t2eand e orbitals by the M-Mπ interaction and are consistent with the value of Jπ≈ 7000 cm−1obtained from a recent analysis of the double excitation region of the electronic spectrum of Cs3Mo2Cl92. Show more