Sequential monte carlo and quantum mechanics calculation of the static dielectric constant of liquid argon

Abstract

A combined and sequential use of Monte Carlo simulation and quantum mechanics calculations is made to obtain the static dipole polarizability, and the related dielectric constant of atomic argon, in the liquid phase. Using Metropolis Monte Carlo simulation, within the NPT ensemble, the structure of liquid argon is obtained at T∈=∈91.8 K and P∈=∈1.8 atm. Seventy statistically relevant configurations are sampled for quantum mechanical calculations of the static dipole polarizability. Each configuration is composed of 14 Ar atoms, corresponding to the first solvation shell. Using these structures' density-functional theory, calculations are performed within the B3P86 hybrid functional and the aug-cc-pVDZ basis set to obtain statistically converged values for the dipole polarizability. Three different models are used to extract the polarizability per atom. From the calculated density and dipole polarizability, the static dielectric constant is obtained using the simple Clausius-Mossotti relation. Our best result indicates a dipole polarizability of 11.6 a 03 and a dielectric constant of 1.52 in agreement with an experimentally available result of 1.53. © 2010 Springer Science+Business Media B.V.