Jung Yousung, Lochan Rohini C, Dutoi Anthony D, Head-Gordon Martin
Department of Chemistry, University of California, Berkeley, California 94720, USA.
J Chem Phys. 2004 Nov 22;121(20):9793-802. doi: 10.1063/1.1809602.
A simplified approach to treating the electron correlation energy is suggested in which only the alpha-beta component of the second order Møller-Plesset energy is evaluated, and then scaled by an empirical factor which is suggested to be 1.3. This scaled opposite-spin second order energy (SOS-MP2), where MP2 is Møller-Plesset theory, yields results for relative energies and derivative properties that are statistically improved over the conventional MP2 method. Furthermore, the SOS-MP2 energy can be evaluated without the fifth order computational steps associated with MP2 theory, even without exploiting any spatial locality. A fourth order algorithm is given for evaluating the opposite spin MP2 energy using auxiliary basis expansions, and a Laplace approach, and timing comparisons are given.
本文提出了一种处理电子相关能的简化方法，该方法仅评估二阶莫勒-普莱塞特能量的α-β分量，然后通过一个建议值为1.3的经验因子进行缩放。这种缩放后的反自旋二阶能量（SOS-MP2，其中MP2是莫勒-普莱塞特理论），在相对能量和导数性质方面产生的结果在统计上比传统的MP2方法有所改进。此外，即使不利用任何空间局部性，也可以在不进行与MP2理论相关的五阶计算步骤的情况下评估SOS-MP2能量。给出了一种使用辅助基展开和拉普拉斯方法来评估反自旋MP2能量的四阶算法，并进行了计时比较。
