High-resolution Raman spectroscopy of the ν1 region and Raman-Raman double resonance spectroscopy of the 2ν1-ν 1 band of 32SF6 and 34SF 6. Determination of the equilibrium bond length of sulfur hexafluoride

摘要

The ν1 region of 32SF6 and 34SF6 has been studied by stimulated Raman spectroscopy. For both isotopomers, a detailed analysis has been performed. Several hot bands (ν1+ν6-ν6, ν1+2ν 6-2ν6, ν1+ν5-ν 5) have been taken into account to calculate synthetic spectra that satisfactorily reproduce the experimental data. These results, together with the previous studies of the other fundamental bands have allowed us to determine the equilibrium bond length of sulfur hexafluoride as r e=1.5560(1) Å, in very good agreement with recent ab initio calculations. The 2ν1-ν1 band has also been studied for both isotopomers by Raman-Raman double resonance spectroscopy and the resulting spectra have been analyzed. In this case, a striking difference is observed between the two isotopomers, since the 2ν1-ν 1 band of 34SF6 appears to have a very narrow structure that could not be rotationally resolved under the present experimental conditions. All analyses have been performed thanks to the HTDS program suite (http://www.u-bourgogne.fr/LPUB/hTDS.html) dedicated to octahedral XY6 molecules. © 2004 Elsevier Inc. All rights reserved.