BeH分子基态振动能级与光谱常数的理论研究

利用Molpro程序包提供的多种方法及基组对BeH分子基态(X2∑+)进行优化计算,结果表明,当选用多参考组态相互作用(MRCI)方法和基组aug-cc-pVQZ进行优化计算时,得到的平衡核间距及离解能与实验值符合较好.在该方法下对BeH分子进行单点能扫描,将得到的分子势能代入分子核运动的Schr9dinger方程,求解该方程获得了BeH分子X2∑+态J=0时的12个振动态,对于每个振动态,分别计算了其振动能级G(v)、转动惯性常数Bv及离心畸变常数Dv,同时进一步导出的光谱常数也与实验值较为吻合.

Theoretical study of vibrational energy levels and spectroscopic constants for the ground state of BeH molecule

Optimization calculation is performed using different basis sets and methods for the ground state()of BeH molecule. Result show that the multi-reference configuration interaction(MRCI) method with aug-cc-pVQZ basis set for BeH molecule is the best group for calculating the equilibrium geometry, the dissociation energy. Potential energy curve(PEC) of BeH molecule have been computed by MRCI/aug-cc-pVQZ. Based on the analytical PEC, 12 vibrational states (J=0) of the ground state of BeH molecule are obtained by numerically solving the radical Schrdinger equation of nuclear motion. For each vibrational state, the vibrational energy levels , inertial rotation constants and the centrifugal distortion constants are calculated. Spectroscopic constants are obtained by fitting to vibrational energy levels and inertial rotation constants . Result show that the calculations are in good agreement with the experimental data.