YC分子基态的结构与势能曲线

Structure and Potential Energy Curve of the Ground State of YC Molecule

考虑到研究对象的相对论效应和电子相关效应,对于YC双原子分子,对Y采用赝势基组,C原子选用6-311+G(3df)和AUG-cc-PVTZ基组,计算方法使用Becke的交换泛函和三参数混合泛函形式即B3LYP杂化泛函方法,首先对YC双原子分子的最优结构进行了计算,由此得到分子的稳定构型、最低能量和振动频率.基于原子分子反应静力学原理,推导得到YC双原子分子基态的合理离解极限.通过对比以往文献报道的实验和高水平理论计算结果,发现CRENBL ECP/6-311+G(3df)混合基组为对体系进行计算最为合适.因此,就在B3LYP/CRENBL ECP/6-311+G(3df)理论水平进一步对YC双原子分子基态的势能面进行了刚性扫描.基于扫描结果,并采用最小二乘法拟合,得到了10参数的Murrell-Sorbie势能函数曲线.由曲线系数(D_e,a_1,a_2,a_3,a_4)进一步计算得到了二、三、四阶力常数(f_2,f_3,f_4)以及相关光谱数据(B_e,α_e,ω_e,ω_eχ_e,D_e).为原子分子碰撞研究提供了有效的数据支持.

In view of the relativistic effect and the electron correlation effect for YC diatomic molecule,using pseudo potential basis set for Y atom and 6-311 ＋ G（ 3df） as well as AUG-cc-PVTZ basis set for C atom,the optimal structure of YC diatomic molecule is calculated using Becke＇s nonlocal three-parameter exchange and correlation functional with the Lee-Yang-Parr correlation functional,B3 LYP. And the stable geometry,ground state＇s energy,along with harmonic frequency are obtained. Based on the theory of atomic and molecular statics,the reasonable dissociation limit of the ground state of YC diatomic molecule is derived. By comparing the results of calculations with the existing experimental and high accuracy theoretical calculation values that literature reported,it can concluded that the mixed basis sets CRENBL ECP /6-311 ＋ G（ 3df） is the most suitable for the calculation of the molecule. Accordingly,the potential energy surfaces of ground state for YC diatomic molecule has been rigid scanned at the B3 LYP / CRENBL ECP /6-311 ＋ G（ 3df） level. On account of the results of scanning,Murrell-Sorbie potential energy function curve with ten parameters is gained by least square fitting. The quadratic,cubic and quartic force contants（ f2,f3,f4） as well as spectroscopic data（ Be,αe,ωe,ωeχe,De） are calculated according to curve＇s coefficients（ De,a1,a2,a3,a4）. The studies provide effective data support for the research of atomic and molecule collision.