Dipole Transition Moments of Chromate Ion

Abstract

A LCAO–MO parametric calculation of chromate ion in terms of a single quantity β , the ligand mixing coefficient, has been carried out. The values of both dipole length (Q theoret L ) and dipole velocity (Q theoret V ) transition moments for 1 A 1 → 1 T 2 (t 1 → 2e) transition of the chromate ion have been computed as functions of ligand mixing coefficient on the bases of Slater‐type of orbitals (STO's) and more exact AO's formed by combination of 2p STO's with double‐ζ3d AO's which duplicate as nearly as possible the SCF AO's. The contribution of charge transfer integral (Q 1 ) and one‐center (Q 2 ) and two‐center (Q 3 ) ligand integrals to the transition moments as functions of β have also been estimated. Whereas Q theoret V is sensitive, Q theoret L is insensitive to change in the 3d radial function. The dipole transition moments are in better agreement with the experimental value when the Richardson's orbitals are used instead of STO's. The use of dipole velocity operator leads to better results than that of dipole length operator. As a by‐product based on simplifying assumptions, the chromate ion appears to possess less π bonding than the permanganate ion.