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本文从体系总能量出发,导出一个表征原子间相互作用能的解析形式,同时基于以键序形式表达的格林函数非对角元,利用递推方法给出了原子间相互作用能的数值结果,由此用多项式线性回归并结合参数拟合确定了原子间相互作用势的表达式。与键序积分计算相配合,计算了金属Ni的电子结构,给出了随晶格常数变化态密度谱、带宽、费米能级及带结构能的变化规律和特征。
Based on the total energy of the system, this paper derives an analytic form that can represent the interaction energies between atoms. Based on the non-diagonal elements of Green’s function expressed in the form of key order, numerical results of the interaction energies between atoms are given by using recursion method. Thus polynomial linear regression and combined with parameter fitting determine the expression of the interaction potential between atoms. In conjunction with the calculation of the bond order, the electronic structure of the Ni metal has been calculated. The variation law of the density spectrum, the bandwidth, the Fermi level and the band structure energy of the lattice constant have been given.