-
在电子密度中,可以假定存在一种能产生交换相关能的非局域空穴。通过该假定可将存在于局域密度理论中的电子自相互作用消除。由这种交换相关能所导出的非局域电子密度势具有两方面的作用:一方面会影响到由空穴产生的静电势;另一方面当空穴的大小和形状随其密度变化而引起能量变化时,它也会影响到描述这些变化的项。迄今为止,所有以往曾研究过此问题的国外学者都只考虑了前一方面的影响而忽略后一方面的作用。本文对包含这些项所引起的各种效应进行了全面而严格的检验,并采用了局域近似或完全忽略;若完全忽略会产生各种各样的无序波函数。本文证明对这些项可进行一般的局域估价,这种方法较之于精确处理要简便得多。The electron self-interaction present in local-density theory can be removed by assuming a nonlocal hole in the electron density to generate the exchange-correlation energy. The potential derived from this energy has two contributions: the electrostatic potential from the hole and terms which describe the variation of the energy as the size and shape of the hole varies with density. All previous authors have included the first contribution, but the treatment of the second ranges from neglect to including them exactly. This work examines the effect of including these terms exactly, approximating them locally or neglecting them completely. Complete neglect yields severely distorted wave functions. This work shows how these terms may be generally estimated locally, which is much simpler than treating them exactly.







下载: