PH, PD和PT分子常数理论研究

采用内收缩多参考组态相互作用(MRCI)方法和包含Davidson修正(+Q) 的MRCI方法结合相关一致基aug-cc-pV5Z研究了PH (X³Σ^-, a¹Δ和A³∏)分子的势能曲线. 在同位素质量识别的基础上对势能曲线进行拟合, 得到PH, PD和PT分子各个电子态的光谱常数(T_e, R_e, ω_e, ω_ex_e, α_e和 B_e). 通过与已有实验数据的比较发现, 本文的结果与实验结果非常一致. 对于PH, PD和PT分子的Σ^-电子态, 计算得到了J = 0时的前12个振动态. 对于每一个振动态, 还分别计算了它的振动能级、惯性转动常数和离心畸变常数. 与其他理论结果和实验数据进行比较可知, 本文的结果更精确、更完整. 文中PD和PT分子的光谱常数和分子常数均属首次报导.

Theoretical investigation on molecular constants of PH, PD and PT molecules

The potential energy curves(PECs) of the PH(X~3 E~-,a~1△and A~3Π) are investigated by the highly accurate valence internally contracted multireference configuration interaction(MRCI) method and the MRCI method including the Davidson modification(+Q) in combination with the correlation-consistent basis sets,aug-cc-pV5Z.With these PECs obtained here,the spectroscopic parameters of three isotopologues,PH(X~3E~-,a~1△and A~3Π),PD(X~3E~-,a~1△and A~3Π) and PT(X~3∑~-,a~1△and A~3Π),are determined. These parameters are compared in detail with those previously reported in the literature,and agreement is found between the present results and the experimental data.The values of vibrational level G(v),inertial rotation constant B_v and centrifugal distortion constant D_v for the first 12 vibrational levels of PH(X~3∑~-),PD(X~3∑~-) and PT(X~3∑~-),are calculated when the rotational quantum number J equals zero,which are in agreement with the available measurements.Comparison with the available experimental data shows that the present molecular constants are accurate.