用密度泛函理论的B3LYP方法,分别以6-311++g(df,3pd),6-311g(3d,3p)和6-311++g(3df,3pd)为基函数对NF分子、NF+和NF-离子基态进行几何优化和频率计算,并进行单点能扫描计算.用最小二乘法拟合得到NFX(X=-1,0,+1)分子离子基态的Murrell-Sorbie势能函数.利用得到的解析势能函数计算出的NF分子和NF+离子基态光谱常数(Be,αe,ωe,ωeχe)与实验值符合很好.首次得到NF-离子基态的光谱常数(Be,αe,ωe,ωeχe)和力常数(f2,f3,f4),为NF-离子基态的后期研究提供理论参考.
Density functional theory B3LYP method is used to optimize ground-state structures of NF molecule,NF+ and NF-molecule ions with 6-311+ +g(df,3pd),6-311g(3d,3p) and 6-311+ +g(3df,3pd) basis sets,respectively.Frequency and single-point energy scan for NFX(X=-1,0,+1) are calculated.With the least-square method,spectral parameters(Be,αe,ωe,ωeχe) of NF molecule and NF+ ion ground state are fitting to Murrell-Sorbie functions.Calculated results are in good agreement with experiments.Spectral parameters(Be,αe,ωe,ωeχe) and force constants(f2,f3,f4) of NF-molecular ion ground state are shown.