title: Quantum Monte Carlo for noncovalent interactions: an efficient protocol attaining benchmark accuracy.
abstract: Reliable theoretical prediction of noncovalent interaction energies, which are important e.g. in drug-design and hydrogen-storage applications, is one of the longstanding challenges of contemporary quantum chemistry. In this respect, the fixed-node diffusion Monte Carlo (FN-DMC) method is a promising alternative to the commonly used "gold standard" coupled-cluster CCSD(T)/CBS method due to its benchmark accuracy and favourable scaling, in contrast to other correlated wave function approaches. This work is focused on the analysis of protocols and possible trade-offs for FN-DMC estimations of noncovalent interaction energies, and proposes an efficient yet accurate computational protocol using simplified explicit correlation terms with a favorable O(N(3)) scaling. It achieves results in excellent agreement (mean unsigned error ∼0.2 kcal mol(-1)) with respect to the CCSD(T)/CBS data on a number of complexes, including benzene/hydrogen, the T-shape benzene dimer, stacked adenine-thymine complex and a set of small noncovalent complexes (A24). The high accuracy and reduced computational costs predestinate the reported protocol for practical interaction energy calculations of large noncovalent complexes, where the CCSD(T)/CBS is prohibitively expensive.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic. matus.dubecky@upol.cz petr.jurecka@upol.cz.
authors.forename: Matúš
authors.initials: M
authors.lastname: Dubecký
authors.forename: René
authors.initials: R
authors.lastname: Derian
authors.forename: Petr
authors.initials: P
authors.lastname: Jurečka
authors.forename: Lubos
authors.initials: L
authors.lastname: Mitas
authors.forename: Pavel
authors.initials: P
authors.lastname: Hobza
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
mesh_terms: D019985:Benchmarking; D003198:Computer Simulation; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D009010:Monte Carlo Method; D011789:Quantum Theory; D012984:Software