Myhre Rolf H, Koch Henrik
Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
J Chem Phys. 2016 Jul 28;145(4):044111. doi: 10.1063/1.4959373.
We present an efficient implementation of the closed shell multilevel coupled cluster method where coupled cluster singles and doubles (CCSD) is used for the inactive orbital space and CCSD with perturbative triples (CC3) is employed for the smaller active orbital space. Using Cholesky orbitals, the active space can be spatially localized and the computational cost is greatly reduced compared to full CC3 while retaining the accuracy of CC3 excitation energies. For the small organic molecules considered we achieve up to two orders of magnitude reduction in the computational requirements.
我们提出了一种闭壳层多级耦合簇方法的高效实现，其中耦合簇单双激发（CCSD）用于非活性轨道空间，带微扰三重激发的CCSD（CC3）用于较小的活性轨道空间。使用Cholesky轨道，活性空间可以在空间上定域化，与完整的CC3相比，计算成本大大降低，同时保留了CC3激发能的精度。对于所考虑的小有机分子，我们在计算需求上实现了高达两个数量级的降低。
