Adler Thomas B, Werner Hans-Joachim, Manby Frederick R
Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
J Chem Phys. 2009 Feb 7;130(5):054106. doi: 10.1063/1.3040174.
A local explicitly correlated LMP2-F12 method is described that can be applied to large molecules. The steep scaling of computer time with molecular size is reduced by the use of local approximations, the scaling with respect to the basis set size per atom is improved by density fitting, and the slow convergence of the correlation energy with orbital basis size is much accelerated by the introduction of terms into the wave function that explicitly depend on the interelectronic distance. The local approximations lead to almost linear scaling of the computational effort with molecular size without much affecting the accuracy. At the same time, the domain error of conventional LMP2 is removed in LMP2-F12. LMP2-F12 calculations on molecules of chemical interest involving up to 80 atoms, 200 correlated electrons, and 2600 contracted Gaussian-type orbitals, as well as several reactions of large biochemical molecules are reported.
描述了一种可应用于大分子的局域显式相关LMP2 - F12方法。通过使用局域近似减少了计算机时间随分子大小的急剧缩放，通过密度拟合改善了相对于每个原子基组大小的缩放，并且通过在波函数中引入明确依赖于电子间距离的项，大大加速了相关能随轨道基组大小的缓慢收敛。局域近似导致计算量随分子大小几乎呈线性缩放，而对精度影响不大。同时，在LMP2 - F12中消除了传统LMP2的域误差。报道了对涉及多达80个原子、200个相关电子和2600个收缩高斯型轨道的化学感兴趣分子以及几种大型生化分子反应的LMP2 - F12计算。
