Underwood Daniel S, Yurchenko Sergei N, Tennyson Jonathan, Jensen Per
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
Fachbereich C-Physikalische und Theoretische Chemie, Bergische Universität, D-42097 Wuppertal, Germany.
J Chem Phys. 2014 Jun 28;140(24):244316. doi: 10.1063/1.4882865.
The structure of the purely rotational spectrum of sulphur trioxide (32)S(16)O3 is investigated using a new synthetic line list. The list combines line positions from an empirical model with line intensities determined, in the form of Einstein coefficients, from variationally computed ro-vibrational wavefunctions in conjunction with an ab initio dipole moment surface. The empirical model providing the line positions involves an effective, Watsonian-type rotational Hamiltonian with literature parameter values resulting from least-squares fittings to observed transition frequencies. The formation of so-called 6-fold rotational energy clusters at high rotational excitation are investigated. The SO3 molecule is planar at equilibrium and exhibits a unique type of rotational-energy clustering associated with unusual stabilization axes perpendicular to the S-O bonds. This behaviour is characterized theoretically in the J range from 100-250. The wavefunctions for these cluster states are analysed, and the results are compared to those of a classical analysis in terms of the rotational-energy-surface formalism.
使用新的合成谱线列表研究了三氧化硫(32)S(16)O₃的纯转动光谱结构。该列表将经验模型中的谱线位置与以爱因斯坦系数形式确定的谱线强度相结合，这些强度由变分计算的振转波函数结合从头算偶极矩面得出。提供谱线位置的经验模型涉及一个有效的沃森型转动哈密顿量，其文献参数值来自对观测到的跃迁频率进行最小二乘拟合。研究了在高转动激发下所谓的六重转动能簇的形成。SO₃分子在平衡时是平面的，并且表现出一种独特类型的转动能簇，与垂直于S - O键的异常稳定轴相关。这种行为在理论上在J范围为100 - 250内进行了表征。分析了这些簇态的波函数，并根据转动能表面形式理论将结果与经典分析结果进行了比较。
