EXCITATION PROFILE OF THE RESONANCE RAMAN EFFECT OF URANYL-NITRATE INACETONE

The resonance Raman spectra of uranyl nitrate in acetone were measured at room temperature, using ten output lines (528.7, 514.5, 501.7, 496 .5, 488.0, 476.5, 472.7, 465.8, 457.9 and 454.5 nm) of an argon-ion la ser. The excitation profile of the resonance Raman effect has been obt ained by plotting the relative intensities of the uranyl symmetric str etching vibration at 863 cm(-1) against the laser exciting wavelengths . It is however pointed out that the resonance Raman effect in acetone is not so large in comparison with that in dimethyl sulfoxide (DMSO). The observed excitation profile is found to resemble to the vibronic structure of the electronic absorption spectrum but not completely sup erimpose on it. Such a discrepancy is qualitatively explained by the i nterference effect which occurs noticeably in the uranyl nitrate-DMSO system. Structure in the Raman excitation profile is briefly discussed on the basis of the Albrecht theory. Lastly, the equilibrium conforma tion of the uranyl ion in the excited electronic state is clarified th rough consideration of the scattering intensities of the uranyl symmet ric stretching vibration depending on the wavelengths of laser excitin g lines.