title: Quantum Monte Carlo Methods Describe Noncovalent Interactions with Subchemical Accuracy.
abstract: An accurate description of noncovalent interaction energies is one of the most challenging tasks in computational chemistry. To date, nonempirical CCSD(T)/CBS has been used as a benchmark reference. However, its practical use is limited due to the rapid growth of its computational cost with the system complexity. Here, we show that the fixed-node diffusion Monte Carlo (FN-DMC) method with a more favorable scaling is capable of reaching the CCSD(T)/CBS within subchemical accuracy (<0.1 kcal/mol) on a testing set of six small noncovalent complexes including the water dimer. In benzene/water, benzene/methane, and the T-shape benzene dimer, FN-DMC provides interaction energies that agree within 0.25 kcal/mol with the best available CCSD(T)/CBS estimates. The demonstrated predictive power of FN-DMC therefore provides new opportunities for studies of the vast and important class of medium/large noncovalent complexes.
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.
authors.forename: Matúš
authors.initials: M
authors.lastname: Dubecký
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.
authors.forename: Petr
authors.initials: P
authors.lastname: Jurečka
authors.affiliation: Institute of Physics, Slovak Academy of Sciences , Dúbravská cesta 9, 845 11 Bratislava, Slovakia.
authors.forename: René
authors.initials: R
authors.lastname: Derian
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.|Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hobza
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.
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
authors.affiliation: Department of Physics and CHiPS, North Carolina State University , Raleigh, North Carolina 27695, United States.
authors.forename: Lubos
authors.initials: L
authors.lastname: Mitas