OCS电子基态势能面与振动光谱的理论研究

Potential Energy Surface and Vibrational Spectrum of OCS

本文采用键长-键角内坐标系下的自洽场-组态相互作用方法精确计算了OCS分子的振动高激发态能级,并结合实验观测到的振动能级利用非线性最小二乘法优化电子基态势能函数中的势能参数.由优化所得的势能面计算出的振动激发态能级与50个实验观测到的振动能级比较,标准偏差为0.08cm^(-1).此外,还用该势能面计算了OCS同位素分子的振动能级,计算结果与实验值也十分吻合.

A potential energy surface for the electronic ground state of OCS is optimized by means of the self -consistent field - configuration interaction method using the exact vibrational Hamiltonian in the bond length -bond angle coordinates. In the optimization, the LMF optimizer in the non - linear least - squares refinement is employed to fit the recently observed band origins below 8000 cm-1 . The standard deviation of the final fitting for the 50 vibrational levels is about 0.08 cm-1 with the largest deviation of - 0. 37 cm-1. The vibrational energy levels for some isotopomers of OCS are also investigated using the optimized potential and in excellent agreement with the observed values.