密度泛函方法对SiO分子基态(X^1Σ^+)势能函数的研究

Study on the potential energy function for the ground state (X^1Σ^+) of SiO molecule by density functional theory

利用密度泛函B3P86方法,分别选用STO-3G,D95**,6-311G,6-311++G,6-311++G**,cc-PVTZ基组对SiO分子基态(X1Σ+)进行结构优化计算.通过比较得出,cc-PVTZ基组为对SiO分子基态(X1Σ+)进行结构优化最优基组的结论.使用密度泛函B3P86方法,选用cc-PVTZ基组进行单点能扫描,用正规方程组拟合SiO分子基态(X1Σ+)的Murrell-Sorbie函数,得到解析势能曲线.最后,由得到的解析势能函数计算了相对应的光谱常数(Be,αe,ωe和ωeχe),并与实验值进行了比较.

The structural optimization for the ground state （X^1∑^＋） of SiO molecule has been calculated using density functional theory B3P86 method with the basis sets STO-3G, D95^＊＊, 6-311 G, 6-311 ＋ ＋G, 6-311 ＋ ＋G^＊＊ and cc-PVTZ. The conclusion is draun by comparison that the basis set cc-PVTZ is the most suitable for the structural optimization calculation of the ground state （ X^1∑^＋） of SiO molecule. The analytical potential energy curve for the ground state （ X^1∑^＋ ） of SiO molecule is scanned using B3P86/cc-PVTZ method, and then fitted to the Murrell-Sorbie function using least squares. At last the spectroscopy constants （Be, ae, ωe and we χe ） related to the analytical potential energy function are calculated and compared with the experimental data.