Revised Anisotropic Site Potentials for the Water Dimer and Calculated Properties

Abstract

Two new parametrizations of a recent ab initio polarizable anisotropic site potential for water are presented. The new versions improve the description of the electrostatic interactions, add an explicit charge-transfer term, and use more accurate dispersion coefficients from the recent literature. To assess the merits of the new models, the potential energy surface of the dimer is analyzed and a comparison is made with 12 other polarizable potentials for water in the literature, most of them being currently used in computer simulation. The structure, energy, and harmonic intermolecular frequencies of the stationary points have been determined and compared with the best available ab initio calculations. The energy barriers and pathways for hydrogen atom interchange within the dimer are discussed. The second virial coefficient B(T) of steam between 373 and 973 K, including first-order quantum corrections, is reported. For all the models, the quantum corrections are found to be significant at the lowest temperatures, amounting to 10−15% at 373 K. Roughly 90% of the quantum corrections arise from the rotational degrees of freedom. Among the potentials considered, only those presented in the present work and a few others are really successful in reproducing the experimental results for B(T) in that temperature range.

Water pair potential of near spectroscopic accuracy. I. Analysis of potential surface and virial coefficients

“…5,6 Another series of water potentials was developed by Stone and collaborators. 7,8 The anisotropic site potential ͑ASP͒ of Millot and Stone 7 models the electrostatic and induction effects by using explicitly calculated monomer properties ͑polarizabilities and multipole moments͒ in the form of an asymptotic expansion, the exchange effects by a fit to 350 points calculated with the Hayes-Stone intermolecular perturbation theory ͑IMPT͒, 9 and the dispersion effects by an asymptotic damped expansion with constants calculated by Rijks and Wormer 10 ͑ASP-W͒. The damping parameter in the Tang-Toennies function 11 was assumed to be equal to the exponent modeling the exchange energy.…”

“…The damping parameter in the Tang-Toennies function 11 was assumed to be equal to the exponent modeling the exchange energy. Another version of the potential ͑ASP-S͒ used a fit to 33 ab initio computed dispersion energies by Szczȩśniak et al 12 The ASP potential was modified by Millot et al 8 to produce the ASP-W2 and ASP-W4 potential energy surfaces ͑PESs͒.…”

A transferable H2O interaction potential based on a single center multipole expansion: SCME

“…α i αβ , A i α,βγ and C i γδ,αβ are, respectively, the dipole-dipole, dipole-quadrupole and quadrupole-quadrupole polarizabilities, shown in Table 2. The values employed in the parametrization of our potential were taken from the ASP-W4 potential [57,58], i.e. the experimentally determined [75] values were used for the dipole-dipole polarizability, while the dipole-quadrupole and quadrupolequadrupole polarizabilities were obtained from Hartree-Fock calculations and scaled by 1.25 [57].…”

“…Figure 2 shows the water dimer in its optimal configuration while Table 4 presents a comparison between the results predicted by our potential, the NCC [55] and ASP-W4 [57,58] potentials, and ab initio MP2/aug-cc-pVTZ results. The ASP-W4 and NCC calculations were performed using Orient 3.2 [81], while the Gaussian 98 [82] package was used for the ab initio calculations.…”

“…Polarizable model potentials such as NCC [55] and DC [54] have been shown to give good results for both small clusters and the liquid, and modifications of the DC potential provide an acceptable description of ice [56]. More recently Millot et al [57,58] and Burnham and Xantheas [59,60,61] have presented transferable potentials that reproduce well ab initio results for clusters.…”