YnO(n=16,17,18)分子基态的结构与分析势能函数

摘要

应用密度泛函理论的B3LYP方法,在Y的有效原子实势近似下,O原子选用6-311 +G(3df)和AUG-cc-PVTZ基组,优化计算了YnO(n=16)分子基态的能量,平衡结构,和谐振频率.根据原子分子反应静力学原理,导出了YnO(n=16,17,18)分子基态的合理离解极限.通过优化计算结果和已有的实验数据对比,得出CRENBL ECP/AUG-cc-PVTZ混合基组为对体系进行计算的最优基组.基于此,在B3LYP/CRENBL ECP/AUG-cc-PVTZ水平也对YnO(17,18)进行了结构优化和频率计算,同时对YO分子基态的势能面进行了单点能扫描.并采用最小二乘法拟合得到了相应的Murrell-Sorbie势能函数.计算出了相应的力常数(f2,f3,f4)和光谱常数(Be,ae,ωe,ωexe,De).结果与已有的实验数据吻合的很好.%Based on effective core potential of Y atom, selecting 6-311 + G(3df) ,AUG-cc-PVTZ basis sets for O atom, the energies, equilibrium structure and harmonic frequency of the ground states of YnO (n=16) molecules are calculated using density functional theory(B3LYP). Based on the theory of atomic and molecular statics, the reasonable dissociation limit of the ground states of Y"0(n=16,17,18) molecules are derived. By comparing the results of calculations with the existing experimental values, we consider that the mixed basis sets CRENBL ECP/AUG-cc-PVTZ is the most suitable for the calculation of the molecules. Consequently, optimization and frequency calculation have been done for YnO(w= 17,18) and the potential energy surface of the ground states of YO molecule has been scanned at the B3LYP/ CRENBL ECP/AUG-cc- PVTZ level of the theory. The potential energy curves of the ground states are obtained by least square fitting to the Murrell-Sorbie potential energy function. The spectro-scopic constants (Be, ag, ωe,ωeXe,De) and force constants ((f2,f3,f4)are calculated and compared with experimental results. It indicate that the results of calculations are in good agreement with the experimental data.