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用密度泛函理论B3LYP方法,在6-31G基组水平上,对12个全氟化合物分子进行了全优化计算,得到其分子零点振动能EZPV、热能校正值Eth、恒容热容CVΦ、标准熵SΦ以及配分函数lgQ等热力学参数,并计算了这些分子的电性拓扑状态指数Em.通过最佳变量子集回归建立了电性拓扑状态指数与热力学参数之间的QSPR模型,模型的相关系数R2分别为1.000,1.000,1.000,0.999和1.000,采用逐一剔除法得到的交叉验证相关系数R2cv分别为0.999,1.000,1.000,0.999和1.000,利用建构的数学模型得到热力学性质的相对平均误差分别为0.43%,0.41%,0.46%,0.41%和0.71%.从方程可以看出,F原子取代基数量是影响全氟化合物分子热力学参数大小的主要因素,检验证明所建模型具有良好的稳定性和预测能力.
Using density functional theory (B3LYP) method, 12 perfluorocompounds were fully optimized at 6-31G basis set to obtain molecular zero vibrational energy EZPV, thermal energy correction value Eth, constant capacitance heat capacity CVΦ, standard Entropy SΦ and partition function lgQ were calculated and the electronic topological state index Em of these molecules was calculated.The QSPR model between the electrical topological state index and the thermodynamic parameters was established by regression of the optimal variable subset.The correlation coefficient R2 were 1.000, 1.000, 1.000, 0.999 and 1.000 respectively. The cross-validation correlation coefficients R2cv were 0.999, 1.000, 1.000, 0.999 and 1.000 respectively. The relative mean errors of the thermodynamic properties obtained by using the constructed mathematical model were 0.43%, 0.41%, 0.46%, 0.41% and 0.71% .From the equation, it can be seen that the number of substituent F atoms is the main factor affecting the size of the thermodynamic parameters of the perfluorocompounds. The test shows that the model has good stability and Ability to predict.