REPETITIVE VIBRONIC STRUCTURE PATTERNS AND THE ENERGY-GAP IN THE SPECTRA OF METAL-COMPLEXES CAUSED BY EXCITED-STATE DISTORTIONS

Two unusual features in the electronic spectra of transition metal compounds which result from excited state distortions are the subject of this paper. The first feature, repetitive patterns of vibronic structure, are interpreted in terms of beats in the time domain between the time-dependent overlaps of two or more modes. The patterns which appear in the emission and absorption spectra of bis(maleonitriledithiolato)palladium are analyzed. The second feature, large gaps separating the emission and absorption spectra of some metal complexes, is a consequence of displacements in two or more normal modes, one of which is not totally symmetric. The active asymmetric b1g mode of PtCl42- is modeled by a double minimum potential surface. The electronic spectra and the energy gap are calculated by using the split operator technique for numerical integration of the time-dependent Schrodinger equation.