Department of Physics and Astronomy, University College London, London, WC1E 6BT, United Kingdom.
J Chem Phys. 2013 Nov 28;139(20):204308. doi: 10.1063/1.4832322.
We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H2CS. It covers 41,809 rovibrational levels for states up to J(max) = 30 with vibrational band origins up to 5000 cm(-1) and provides the energies and line intensities for 547,926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.
我们提出了一种变分计算方法，用于计算 T = 300 K 下的第一个全面的硫醛（H2CS）的转动-振动线列表。它涵盖了高达 J(max) = 30 的 41,809 个转动-振动能级，振动带起源高达 5000 cm(-1)，并提供了从基态振动能级到这些能级的 547,926 个跃迁的能量和线强度。它基于我们之前报道的准确的从头算势能面和新计算的从头算电偶极矩面。对从头算平衡几何形状进行了一些微小的经验调整，以减少预测带内转动能级中的系统误差。通过使用计算机程序 TROVE 中实现的方法，通过变分计算得到了转动-振动能级和跃迁强度。跃迁波长和强度与可用的实验数据非常吻合。本计算正确地再现了观察到的共振效应，例如强度借用，从而反映了基础从头算表面的高精度。我们报告了对几个振动带的详细分析，特别是那些受强科里奥利耦合影响的振动带的分析，以方便未来的实验室分配。
