EXCITATION PROFILE OF THE RESONANCE RAMAN EFFECT OF RUBIDIUM URANYL TRINITRATE IN DIMETHYL-SULFOXIDE

The resonance Raman spectra of rubidium uranyl trinitrate in dimethyl sulfoxide were measured at room temperature, using ten output lines (5 28.7, 514.5, 501.7, 496.5, 488.0, 476.5, 472.7, 465.8, 457.9, and 454. 5 nm) of an argon-ion laser. The excitation profile of the resonance R aman effect has been obtained by plotting the relative intensities of the uranyl symmetric stretching mode at 834 cm(-1) against the laser e xciting wavelengths. The observed excitation profile is found to be si milar to the vibronic structure of the electronic absorption spectrum, but not be completely superimposed on it. Transform theory which make s use of the observable electronic absorption spectrum of the resonant electronic state has been applied to predict the Raman excitation pro file under consideration. Comparing the experimental Raman excitation profile with the transform theory prediction, it is found that the res onance Raman intensities of the uranyl symmetric stretching mode depen d mainly on the vibronic interaction (non-Condon effect) in excited el ectronic states. (C) 1997 Elsevier Science B.V.