The resonance Raman effect of uranyl chloride in dimethyl sulfoxide

Abstract

A study was carried out of the resonance Raman scattering spectra of uranyl chloride (UO 2Cl 2) in dimethyl sulfoxide ((CH 3) 2SO) (DMSO) under laser excitation of the UO 2 2+ ion in resonance with the 1Σ + g→ 1Φ g Laport-forbidden f–f electronic transitions span from 530 to 450 nm by using ten output lines of the argon-ion laser at room temperature. The resonance Raman excitation profile of the totally symmetric stretching vibrational mode of uranyl observed at 832 cm −1 is presented and analyzed in terms of transform theory within the non-Condon model to give relatively good agreement with experimental results. The disagreement between the experimental data and the calculated resonance Raman excitation profile, at the long-wave part of the the 1Σ + g→ 1Φ g electronic transitions, may be referred to interference between the weak scattering from the neighboring forbidden electronic states ( 1Δ g) and strong preresonance scattering from allowed electronic states at higher levels. An amount of change in the experimental resonance Raman excitation profile of the uranyl–DMSO system depends considerably upon the ligands (L) bound to the uranyl group. Elongation of the U–O equilibrium bond length resulting from the 1Σ + g→ 1Φ g electronic transitions is related to the magnitude of the change in the excitation profile of UO 2L 2 (L=NO 3, CH 3COO, Cl) type uranyl compounds in (DMSO).