title: Ab initio water pair potential with flexible monomers.
abstract: A potential energy surface for the water dimer with explicit dependence on monomer coordinates is presented. The surface was fitted to a set of previously published interaction energies computed on a grid of over a quarter million points in the 12-dimensional configurational space using symmetry-adapted perturbation theory and coupled-cluster methods. The present fit removes small errors in published fits, and its accuracy is critically evaluated. The minimum and saddle-point structures of the potential surface were found to be very close to predictions from direct ab initio optimizations. The computed second virial coefficients agreed well with experimental values. At low temperatures, the effects of monomer flexibility in the virial coefficients were found to be much smaller than the quantum effects.
authors: †Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States.|§Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.
authors: Piotr
authors: P
authors: Jankowski
authors: †Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States.
authors: Garold
authors: G
authors: Murdachaew
authors: †Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States.
authors: Robert
authors: R
authors: Bukowski
authors: †Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States.
authors: Omololu
authors: O
authors: Akin-Ojo
authors: ‡Institut Charles Gerhardt (CTMM)-UMR 5253, CC 15.01, Université Montpellier II-CNRS, Montpellier, Cedex 05, France 34095.
authors: Claude
authors: C
authors: Leforestier
authors: †Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States.
authors: Krzysztof
authors: K
authors: Szalewicz