Analysis of high-resolution infrared and CARS spectra of ³⁴S¹⁸O₃

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• 作者：Masiello ; Tony ; Barber ; Jeffrey ; Chrysostom ; Engelene t.H. ; Nibler ; Joseph W. ; Maki ; Arthur ; et. al.
• 关键词：Infrared ; Spectrum ; Sulfur trioxide ; Sulfur-34 ; Oxygen-18
• 刊名：Journal of Molecular Spectroscopy
• 出版年：2004
• 期刊代码：129_00222852
• 类别：ch
• 出版时间：January, 2004
• 卷：223
• 期：1
• 页码：84-95
• 文件大小：541 K

摘要

Three fundamental modes and several hot bands of ³⁴S¹⁸O₃ have been investigated using both infrared spectroscopy and coherent anti-Stokes Raman scattering spectroscopy (CARS). Coriolis coupling effects are particularly noticeable in ³⁴S¹⁸O₃ due to the close proximity of the ν₂ and ν₄ fundamental vibrations, whose wavenumber values are 477.50864(5) and 502.05565(4)cm⁻¹. The uncertainties in the last digits are shown in parentheses and are two standard deviations. Hot band transitions from ν₂, ν₄ levels give access to infrared inactive ν₂, ν₄ combination/overtone levels which interact strongly with levels of the Raman-active ν₁ symmetric stretching mode due to indirect Coriolis couplings, l-resonances, and Fermi resonances. The result is a complex ν₁ CARS Q-branch spectrum that is the most perturbed of the four SO₃ isotopomers we have studied. The relative importance of these interaction terms on the ν₁ CARS spectrum is examined in some detail and accurate rovibrational constants are determined for all of the mixed states, leading to deperturbed values of 1004.662(24), 0.0003503(9), and 0.0007066(12)cm⁻¹ for ν₁, α₁^B, and α₁^C, respectively. The B_e value is found to be 0.310875(12)cm⁻¹, which gives an equilibrium bond length r_e of 141.7339(3)pm, in excellent agreement with values of 141.7340(1) and 141.7347(7)pm reported earlier for ³²S¹⁶O₃ and ³⁴S¹⁶O₃.