title: Molecular hydrogen adsorbed on benzene: Insights from a quantum Monte Carlo study.
abstract: We present a quantum Monte Carlo study of the hydrogen-benzene system where binding is very weak. We demonstrate that the binding is well described at both variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC) levels by a Jastrow correlated single determinant geminal wave function with an optimized compact basis set that includes diffuse orbitals. Agreement between VMC and fixed-node DMC binding energies is found to be within 0.18 mhartree, suggesting that the calculations are well converged with respect to the basis. Essentially the same binding is also found in independent DMC calculations using a different trial wave function of a more conventional Slater-Jastrow form, supporting our conclusion that the binding energy is accurate and includes all effects of correlation. We compare with previous calculations, and we discuss the physical mechanisms of the interaction, the role of diffuse basis functions, and the charge redistribution in the bond.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801, USA. beaudet@uiuc.edu
authors.forename: Todd D
authors.initials: TD
authors.lastname: Beaudet
authors.forename: Michele
authors.initials: M
authors.lastname: Casula
authors.forename: Jeongnim
authors.initials: J
authors.lastname: Kim
authors.forename: Sandro
authors.initials: S
authors.lastname: Sorella
authors.forename: Richard M
authors.initials: RM
authors.lastname: Martin