X^1∑^+态NaX(X=Br,F)分子势能函数与光谱常数

Potential energy functions and spectroscopic constants for the states X^1∑^+ of molecule NaX(X=Br,F)

采用群论及分子反应静力学原理,推导其Na Br和Na F分子基态电子态和合理的离解极限。运用Gaussian03程序中的多种方法和基组,计算分子的几何结构、离解能以及谐振频率,对Na Br分子选取B3LYP/6-311g(2df,2pd)为最优方法与基组,对Na F分子选取BP86/6-31g(3df,3pd)为最优方法与基组,分子在最优方法与基组下进行能量扫描,采用Murrell-Sorbie函数进行了非线性最小二乘法拟合得到分子势能函数,从而计算Na Br和Na F分子的力常数与光谱常数,与实验值对照,计算得到光谱常数值与实验值吻合甚好。

The ground electronic state X^1∑~＋and dissociation limit of Na Br and Na F molecular have been correctly determined based on group theory atomic and molecular reaction statics. The equilibrium geometries,dissociation energy and harmonic frequencies of the ground state Na Br and Na F have been calculated using several methods in conjunction with different basis sets. For the Na Br molecular,It way chosen the B3 LYP /6- 311g（ 2df,2pd） as the best method and basis sets. For the Na F molecular,It way chosen the BP86 /6- 31g（ 3df,3pd） as the best method and basis sets. The whole potential curves for the ground electronic state have been scanned using the best method and basis set,the potential energy function of molecular have been obtained by least square fitting to the Murrell-Sorbie function. At the same time,the force constants and spectroscopic constants have been calculated.Comparing to the computation results,the present results were in good agreement with the experimental values.