posted on 2023-11-03, 09:00authored byYuqi Wang, Yang Guo, Frank Neese, Edward F. Valeev, Wei Li, Shuhua Li
In
this article, we present a series of explicitly correlated local
correlation methods developed under the cluster-in-molecule (CIM)
framework, including explicitly correlated second-order Møller–Plesset
perturbation (MP2), coupled-cluster singles and doubles (CCSD), domain-based
local pair natural orbital CCSD (DLPNO-CCSD), and DLPNO-CCSD with
perturbative triples (DLPNO-CCSD(T)). In these methods, F12 correction
is decomposed into contributions from each occupied local molecular
orbital and then evaluated independently in a given cluster, which
consists of a subset of localized orbitals. These newly developed
methods allow F12 calculations of large molecules (up to 145 atoms
for quasi-one-dimensional systems) on a single node. We use these
methods to investigate the relative stability between extended and
folded alkane C30H62, the relative stability
of four secondary structures of a polyglycine Ace(Gly)10NH2, and the binding energies of two host–guest
complexes. The results demonstrate that the combination of CIM with
F12 methods is a promising way to investigate large molecules with
small basis set errors.