CALCULATION OF VIBRONIC COUPLING-CONSTANTS FOR TETRAHEDRAL AND OCTAHEDRAL D-ELECTRON-SYSTEMS VIA DYNAMIC LIGAND-FIELD THEORY AND APPLICATION TO OPTICAL-SPECTRA

A perturbative model for the calculation of electron-phonon coupling c onstants of tetrahedral transition metal complexes based on the electr ostatic ligand field theory is presented. Orbital vibronic coupling co nstants are expressed in terms of common ligand field parameters, and linear many-electron coupling constants fbr all d(2)-d(9) strong field states in tetrahedral and octahedral symmetry are reduced to orbital coupling constants, enabling comparisons of coupling strength and dire ctions of nuclear distortions over a wide range of transition metal co mplexes in a general way. The usefulness of the model is demonstrated for well resolved optical spectra of tetrahedral [MnO4](2-), [CrO4](3- ), [CoCl4](2-) and octahedral [CrF6](3-), [Cr(NH3)(6)](3+), [VO6](8-) complexes, revealing good correspondence. The method is especially val uable for the interpretation of such spectra because it is easy to app ly and the prediction of band shapes does not require additional param eters to be fitted to experiment. Nuclear distortions from the cubic r eference geometry and Jahn-Teller stabilization energies are calculate d.