以密度泛函理论及相关方法计算电负性标度

Electronegativity Scale of Elements Calculated by Density Functional Theory and Related Methods

在化学及相关领域里电负性是非常基本的重要概念 ,而电负性标度是极其有用的理化参数。应用密度泛函数理论及其局域密度近似、局域密度近似加非局域性校正和改进的Slater过渡态方法 ,并在计算中考虑了相对论效应 ,把元素的电离能和电子亲合能的计算扩展到周期表的 10 7种元素 ,并依据能量型标度的定义式 ,采用有限差分方法计算了这 10 7种元素的电负性及其标度。同时计算结果较以前文献报道同样根据密度泛函理论但使用其它方法诸如近似的交换相关泛函数的计算结果有所改进 ,与实验值更为接近。该电负性新标度将在分子结构参数化表达。

In chemistry and many related fields, electronegativity (EN) is an important fundamental concept and its scale is a useful physcochemical parameter. Here, calculations of both ionization potentials and electron affinities are extended toward 107 elements and done by density functional theory at the local density approximation(LDA) level and the LDB level, i.e., the local density approximation level with further non-local corrections for exchange and correlation included self-consistently as well as the modified Slater transition-state method. The definite-differentiation method is employed into calculations of the electronegativity scale and the related parameters of 107 elements with very good results due to the consideration of relativistic effects. The calculation presented is to examine both the LDA and LDB approximations in calculations for the ionization potential and electron affinity of the elements with an improved or modified Slater transition-state method, and relativistic effects have also been taken into account for 107 elements compared with 103, 86 or less in the previous report under a spin polarized density function theory with some approximations to the exchange-correlation function. The calculation results for the various quantities represent an obviously improvement over some previous calculations. It is shown that the results calculated by the extended technique and the improved Slater transition-state method in general agree well with experimental values presented by Pearson, and are better than the reported values in many previous literatures. The developed new electronegativity scale will widely be applicable in many fields such as molecular structural parameterization expression, chemobiological activity optimization prediction, structure-activity quantitation modeling, functional chemical adaptization designing, and so on.