CF和CF_2分子的结构与势能函数

Structure and Potential Energy Function Investigation on CF and CF_2 Molecule

应用密度泛函B3LYP方法,采用6-311++G(3df,3pd)基组对CF(X2Π)进行了理论计算,得到了它的微观几何结构,力学性质和光谱性质,结果表明:CF的平衡核间距为0.127 21 nm,基态的理解能为5.793 eV,谐振频率为1 299.95 cm-1,与实验值符合得非常好,并得到了它的Murrell-Sorbie势能函数.应用密度泛函B3P86/6-311++G(df,pd),优化出CF2(X1A1)分子稳定构型为C2V,其平衡核间距为Re=0.129 74 nm,∠FCF=104.64°,同时计算出了离解能、力常数及谐振频率.在此计算基础上,应用多体展式理论方法,导出了基态CF2分子的解析势能函数,该势能面准确反映了CF2(X1A1)分子的结构特征和能量变化.

Equilibrium geometry, force property and spectroscopy property of CF（X^2 Ⅱ） molecule have been calculated using the B3LYP method with the basis set 6-311d-q-G（3df, 3pd） . The equilibrium nuclear distance, dissociation energy and harmonic frequency are 0. 127 21 nm, 5. 793 eV and 1. 299 95 cm^-1 ,which are in good agreement with experimental value . Meanwhile the Murrell-Sorbie potential function of CF（X^2 Ⅱ） molecule is obtained. Using the B3P86 method with the basis set 6-311 ＋＋G（df, pd）, the present work has optimized the equilibrium geometry for the ground state X^1 A1 of CF2, which is C2v F-C-F ,whose angle, equilibrium nuclear distance, are 104.64°, 0. 129 74 nm and dissociation energy respectively , and its harmonic frequencies , force constants have been calculated. Analytical potential energy function for the ground state X^1A1 of CF2, has been derived using many-body expansion method . The structure and energy of CF2 can correctly reappear on the potential surface.