【摘要】 本文提出一个新的扩大模型空间的方案用于改进多参考态二级微扰理论(MRPT2)计算.新方案保持了原方案中扩大模型空间之前的简单程序结构,理论上完全可以避免势能面计算中入侵态的出现,并在一系列比较计算中得到证实.新MRPT2程序是研究分子激发态和电子光谱的有用工具.更多还原

【Abstract】 A new scheme with extended model space is proposed to improve the calculation of multi-reference second order perturbation theory (MRPT2). The new scheme preserves the concise code structure of the original program, and can avoid intruder states in constructions of potential energy surface, which is confirmed by a series of comparable calculations. The new MRPT2 program is an available tool for the research of molecular excited states and electronic spectrum.更多还原