取代乙烷交叉式与重叠式稳定性的密度泛函理论研究

Study on the Stability of Substituted Ethane With Eclipsed Form and Staggered Form by Density Functional Theory

在密度泛函DFT/B3LYP理论水平优化结构,结合Aug-CC-pVDZ基组计算了17种取代乙烷交叉式与重叠式的电子能量。结果发现,相关能差值(ΔEc)与总能量差值(ΔE)的相关回归系数最高(R^2=0.95),交换能差值(ΔEx)与ΔE相关回归系数次之(R^2=0.93)。选择ΔEc与ΔEx对ΔE进行多元线性拟合,得到其相关回归系数(R^2=0.95),再用拟合公式计算ΔE(实际),并与计算得到的ΔE(理论)进行线性拟合,得到其相关回归系数R^2=0.95。我们认为,交叉式取代乙烷的构象稳定性主要起源于其分子内的相关能(Ec)和交换能(Ex)作用。

Through optimizing the structure in the density functional theory DFT/B3 LYP level, combined with Aug-CC-p VDZ basis set, electron energy of 17 kinds of substituted ethane with eclipsed form and staggered form was calculated. The results show that the correlation regression coefficient of correlation energy difference（ΔEc） and total energy difference（ΔE） is the highest（R^2 = 0.95）, the correlation regression coefficient of exchange energy difference（ΔEx） and total energy difference（ΔE） is the second（R^2 = 0.93）.ΔEc and ΔEx were used to carry out multivariate linear regression on ΔE, correlation regression coefficient was obtained（R^2 = 0.95）, and then fitting formula was used to calculate ΔE（actual）, and the linear fitting of ΔE（actual） and calculated ΔE（theoretical） was carried out to obtain its correlation regression coefficient R^2 = 0.95. It＇s pointed out that the conformational stability of substituted ethane with staggered form depends on correlation energy（Ec） and exchange energy（Ex）.