Theoretical study of vibrational overtone spectroscopy and dynamics of methanol
Theoretical study of vibrational overtone spectroscopy and dynamics of methanol
复制标题
甲醇振动泛音光谱与动力学的理论研究
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
L. Halonen
中科院分区：
文献类型：
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作者：
L. Halonen
实验观察到的高泛音区域中 OH 和 CH 伸缩模式之间的耦合已根据曲线内坐标哈密顿量成功建模，包括非简谐 OH 和 CH 伸缩振荡器之间的谐波耦合以及 CH 伸缩和 HCH 弯曲之间的立方费米共振动能和势能耦合。哈密顿矩阵被设置为仅包括谐振态的块对角形式。使用实验振动项值作为数据，通过最小二乘法优化了势能参数。获得的 OH/CH 拉伸相互作用参数与通过微扰理论从已发表的从头算谐波力场计算得到的参数非常吻合。该模型在 OH 拉伸泛音区域中很好地再现了实验频带起源，并且为 CH 拉伸基本区域中的弯曲泛音提供了分配。最后，从内坐标表示中找到酉变换……
Experimentally observed coupling between OH and CH stretching modes in the high overtone region has been modeled successfully in terms of a curvilinear internal coordinate Hamiltonian including harmonic coupling between anharmonic OH and CH stretching oscillators and cubic Fermi resonance kinetic and potential energy couplings between CH stretches and HCH bends. The Hamiltonian matrices have been set up in block diagonal forms including only resonant states. The potential-energy parameters have been optimized by the least-squares method using experimental vibrational term values as data. The OH/CH stretch interaction parameter obtained agrees well with the one calculated by perturbation theory from a published ab initio harmonic force field. The model has reproduced well experimental band origins in the OH stretching overtone region, and it has provided assignments for the bending overtones in the CH stretching fundamental region. Finally, a unitary transformation is found from the internal coordinate rep...