YH,YD,YT分子基态的结构与势能函数

在Y的有效核势近似下, 对H分别选6-311++G(3df,2pd), AUG-cc-PVTZ, AUG-cc-PVQZ基组, 应用密度泛函理论的B3LYP方法, 优化计算了YH(D,T)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YH(D,T)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和理论数据对比, 得出LANL2TZ/AUG-cc-PVQZ混合基组为对体系进行计算的最优基组. 基于此, 在B3LYP/LANL2TZ/AUG-cc-PVQZ水平对YH(D,T)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. 计算出了这些分子的力常数(f₂, f₃, f₄)和光谱常数(B_e, α_e, ω_e, ω_eχ_e, D_e).结果与已有的实验数据符合得很好.

Structures and potential energy functions of the ground states of YH,YD,YT molecules

Using the density functional theory（B3LYP） method,the 6-311++G（3df,2pd）,AUG-cc-PVTZ,AUG-cc-PVQZ basis sets for H and effective core potentials for Y,the energies,equilibrium structure and harmonic frequency of the ground states of YH（D,T） molecules are calculated.Based on the theory of atomic and molecular reaction statics,the reasonable dissociation limits of the ground states of YH（D,T） molecules are derived.By comparing the calculation results with the existing experimental and theoretical values, we find that the mixed basis sets LANL2TZ/AUG-cc-PVQZ are most suited for the calculation of the molecules.Consequently,the potential energy surfaces of the ground states of YH（D,T） molecules are scanned at the B3LYP/LANL2TZ/AUG-cc-PVQZ level of theory.The potential energy curves of the ground states of YH（D,T） molecules are obtained by the least square fitting to the Murrell- Sorbie potential energy function.The spectroscopic constants(B_e,α_e,ω_e,ω_eχe,D_e) and force constants(（f₂,f₃,f₄）are calculated and compared with experimental results,indicating that the calculation results are in good agreement with the experimental data.