氢链中的Peierls机理(Ⅰ) Hartree-Fock解的二聚化

PEIERLS MECHANISM OF HYDROGEN CHAIN (Ⅰ) THE DIMERIZATION OF THE HARTREE-FOCK SOLUTIONS

本文对无限长氢链中是否存在Peierls不稳定性做ab initio计算的研究,利用高斯型轨道基组和无限长氢链的周期性,在近邻基础上,构造出一组完备的正交归一的基波函数,解析对角化Fock矩阵,做限制的Hartree-Fock的分子轨道自洽场中原子轨道线性组合(LCAO-MO-SCF)计算,总能量与二聚化的关系曲线E_(RHF)(u)表明,金属氢链基态是不稳定的,无限长氢链中会出现明显的二聚化,Peierls不稳定性依然在这一体系中有具体的表现。

Ab initio study has been used to explore the problem if the Peierls instability in hydrogen chain presents or not. With a Gaussian-type-orbital basis set and periodicity of hydrogen chain, we construct a complete set of orthogonal and normalized wave functions in view of the second-neighbor approximation. Starting from the restricted Hartree-Fock scheme, we diagnoalize the Fock matrix analytically and calculate the LCAO-MO-SCF solutions. The dependence of the total energy on dimerization is analyzed, it is shown that the ground state of metal hydrogen chain is unstable, and that obvious dimerization may occur in infinite hydrogen chain. The Per erls instability presents in this system nevertheless.