Ab initio calculation of intermolecular potentials and second virial coefficients for monte carlo simulation of dimer N2-N2
The results presented in this paper are the ab initio intermolecular potentials and the second virial coefficient, B2 (T) of the dimer N2-N2. These ab initio potentials were proposed by the quantum chemical calculations at high level of theory CCSD(T) with basis sets of Dunning’s valence correlation-consistent aug-cc-pVmZ (m = 2, 3); these results were extrapolated to complete basis set limit aug-cc-pV23Z. The ab initio energies of complete basis set limit aug-cc-pV23Z resulted from the exponential extrapolation were used to construct the 5-site pair potential functions. The second virial coefficients for this dimer were predicted from those with four-dimensional integration. The virial coefficients of them described accurately by the ab initio Lennard-Jones and Morse-style potentials. These potentials were also used for prediction of thermodynamics properties of vapor-liquid equilibria by Gibbs Ensemble Monte Carlo simulation (GEMC). The simulation results were also compared to those from equation of state. The obtained results turned out to be good agreement with experimental data.