MRCI study on potential energy curves, spectroscopic parameters and rovibrational energy levels of CS(X¹Σ⁺) molecule

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• 作者：De-Heng Shi ; Hui Liu ; Jin-Feng Sun ; Yu-Fang Liu ; Zun-Lue Zhu
• 关键词：Rovibrational energy level ; Spectroscopic parameter ; Inertial rotation constant ; Centrifugal distortion constant ; Classical turning point
• 刊名：Journal of Molecular Structure: THEOCHEM
• 出版年：2010
• 出版时间：15 April 2010
• 年：2010
• 卷：945
• 期：1-3
• 页码：1-7
• 全文大小：204 K

文摘

Using the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with several groups of correlation-consistent basis sets, this paper investigates the potential energy curves (PECs), spectroscopic parameters and vibrational manifolds including rovibrational levels and transition lines of the CS(X¹Σ⁺) molecule. The PECs are fitted to the Murrell–Sorbie function form, which are used to accurately reproduce the spectroscopic parameters (D₀, ω_eχ_e, α_e and B_e). By comparison with the available experiments, the PEC obtained at the basis sets, aug-cc-pCV5Z for C and cc-pV5Z for S, is selected to investigate the spectroscopic parameters and rovibrational energy levels. The present D₀, D_e, R_e, ω_e, ω_eχ_e, α_e and B_e are of 7.2646 eV, 7.3436 eV, 0.15403 nm, 1278.00 cm⁻¹, 6.4924 cm⁻¹, 0.005837 cm⁻¹ and 0.8144 cm⁻¹, respectively, which almost perfectly conform to the available measurements. With the interaction potential obtained at the basis sets, aug-cc-pCV5Z for C and cc-pV5Z for S, by numerically solving the radial Schrödinger equation of nuclear motion, a total of 82 vibrational states is predicted when the rotational quantum number J equals zero. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0, which are in excellent agreement with the available experiments. The rovibrational energy levels of the CS(X¹Σ⁺) molecule are calculated until J = 30. According to the rovibrational levels, a number of transition lines for the CS(X¹Σ⁺) molecule are evaluated, which agree well with the available experimental observations.