title: Closed-shell ring coupled cluster doubles theory with range separation applied on weak intermolecular interactions.
abstract: We explore different variants of the random phase approximation to the correlation energy derived from closed-shell ring-diagram approximations to coupled cluster doubles theory. We implement these variants in range-separated density-functional theory, i.e., by combining the long-range random phase approximations with short-range density-functional approximations. We perform tests on the rare-gas dimers He(2), Ne(2), and Ar(2), and on the weakly interacting molecular complexes of the S22 set of Jurečka et al. [P. Jurečka, J. Šponer, J. Černý, and P. Hobza, Phys. Chem. Chem. Phys. 8, 1985 (2006)]. The two best variants correspond to the ones originally proposed by Szabo and Ostlund [A. Szabo and N. S. Ostlund, J. Chem. Phys. 67, 4351 (1977)]. With range separation, they reach mean absolute errors on the equilibrium interaction energies of the S22 set of about 0.4 kcal/mol, corresponding to mean absolute percentage errors of about 4%, with the aug-cc-pVDZ basis set.
authors: Laboratoire de Chimie Théorique, Université Pierre et Marie Curie and CNRS, 75005 Paris, France. julien.toulouse@upmc.fr
authors: Julien
authors: J
authors: Toulouse
authors: Wuming
authors: W
authors: Zhu
authors: Andreas
authors: A
authors: Savin
authors: Georg
authors: G
authors: Jansen
authors: János G
authors: JG
authors: Ángyán