High-level ab initio studies of the structure,vibrational spectra,and energetics of S_3

摘要

Observation of mass-dependent and non-mass-dependent sulfur isotope fractionations in elemental sulfur is providing new insight into the nature of the sulfur cycle in the atmosphere.Interpretation of the experimental isotope data requires estimation of the energetics for the reaction S + S_2->S_3(isoelectronic with O+O_2->O_3).Key molecular properties of the S_3 potential-energy surface,such as vibrational frequencies and isotopic shifts,are presented that can be used to assess the mass-dependent fractionation effect.Ab initio results are compared to the available experimental results for S_2 to evaluate the reliability of the computational results for S3.The S-S bond dissociation energy for S_3 is determined to be 60.9(+-)1 kcalmol~(-1).