Department of Chemistry, Rice University, Houston, Texas 77005, USA.
J Chem Phys. 2009 Oct 21;131(15):154106. doi: 10.1063/1.3250834.
We recently presented a combination of a short-range density functional approximation with long-range random phase approximation (RPA) correlation [B. G. Janesko, T. M. Henderson, and G. E. Scuseria, J. Chem. Phys. 130, 081105 (2009)]. Here we explore how this approximation's performance is affected by the choice of reference state, i.e., the orbitals and orbital energy differences entering the RPA energy expression. Our previous results built the reference state using a nonlocal exchange potential. Rescaling the RPA correlation energy by an empirical factor >1 gave very accurate results for a wide range of properties. We show here that reference states constructed from approximate local exchange-correlation potentials give their best results with smaller rescaling factors approximately 1. However, the tested potentials yield artifacts in some systems.
我们最近提出了一种短程密度泛函近似与远程随机相位近似（RPA）相关的组合[B. G. Janesko、T. M. Henderson 和 G. E. Scuseria，J. Chem. Phys. 130, 081105 (2009)]。在这里，我们探讨了这种近似的性能如何受到参考状态的选择的影响，即进入 RPA 能量表达式的轨道和轨道能差。我们之前的结果使用非局部交换势构建了参考状态。通过经验因子>1 对 RPA 相关能量进行缩放给出了广泛性质的非常准确的结果。我们在这里表明，从近似的局域交换相关势构建的参考状态在较小的缩放因子（约为 1）下给出最佳结果。然而，测试的势在一些系统中产生了伪影。
