在计算LiH晶体结合能时,将离子间多体关联效应和离子压缩效应当作两个独立的物理机理同时引入晶体能量表达式,未引入可调参数而直接计算电子交换能.结果表明多体交换关联效应对体系的常压和高压特性都具有显著影响.当考虑最邻近和次邻近离子贡献时,等温状态方程的计算结果与实验观测数据在0—90GPa压力范围相一致.
When the cohesive energy of LiH is calculated, the many-body correlation effect between ions and the contraction of ionic orbital are included, as two separate physical mechanisms in the total energy formula. The exchange-energy between electronic orbitals is directly computed without any adjustable parameters introduced. The results showed that many-body exchange- correlation effects markedly influence the properties at zero pressure and under high pressures. When the contributions of the nearest and next-nearest ions were taken into account, the results of the isothermal equation of state is in good agreement with experimental data in the pressure range of 0--90 GPa.