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 (UO2Cl2) in dimethyl sulfoxide ((CH3)2SO) (DMSO) under laser excitation of the UO2(2+) ion in resonance with the 1sigma(g)+ --> 1phi(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 1sigma(g)+ --> 1phi(g) electronic transitions, may be referred to interference between the weak scattering from the neighboring forbidden electronic states (1delta(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 1sigma(g)+ --> 1phi(g) electronic transitions is related to the magnitude of the change in the excitation profile of UO2L2 (L = NO3, CH3COO, Cl) type uranyl compounds in (DMSO).

Electronic spectra of uranyl chloride complexes in acetone: a CASSCF/CASPT2 investigation

“…Uranyl chloride complexes are usually studied in organic solvents. 4,20,21 Structural information can be deduced from either X-ray diffraction [22][23][24] studies on comparable single crystals, or from EXAFS [25][26][27] experi-ments in solution. However, the actual structure and coordination number of uranyl chloride complexes formed in water and in organic solutions still remains to be resolved.…”

“…Density functional theory (DFT) calculations have recently been conducted on the structure of [UO 2 Cl 4 ] 2À both in the gas phase 28,29 and in aqueous solution, 28 and on UO 2 Cl 2 in the gas phase. 21,30,31 The first ab initio calculations on the electronic excited states of uranyl were the SOC-CI calculations of Pitzer and coworkers on free uranyl 14 and Cs 2 UO 2 Cl 4 11 (Denning's crystal). CASSCF/CASPT2 calculations, including spin-orbit coupling (SOC), by Pierloot 7,32 on the same systems resulted in even better agreement with experiment: for [UO 2 Cl 4 ] 2À , excitation energies correspond to within 800 cm À1 and the U-O stretching frequencies of the excited states are accurate to within 10 cm À1 .…”

SERS mapping of nanoparticle labels in single cells using a microfluidic chip

“…Thus both surface enhanced Raman scattering, SERS, and surface enhanced resonance Raman scattering, SERRS, effects have been widely applied to a number of analytical problems. [2][3][4][5] Amongst the earliest and most commonly used surfaces for achieving surface enhancement of the Raman effect involves the use of colloidal metals. 6 In this study, we combined the use of silver colloidal nanoparticles 7 with appropriate reporter molecules capable of binding strongly to the colloid, allowing low levels (sub-nanomolar) of analyte to be reliably detected.…”

Spectra and structure of hexavalent uranium nanoclusters with mixed acido ligands in the coordination sphere

“…The fact is that DMSO is a ligand with rather high donor ability, which can be realized both through the oxygen atom or through the sulfur atom. And it has been established [6,7] that when DMSO coordinates through the oxygen, the S=O bond is weakened and the corresponding frequency decreases by ≈100 cm -1 . If the sulfur atom is involved in the bond, then the S=O vibrational frequency increases by approximately the same amount.…”