The vapor-liquid equilibria of pure fluid hydrogen were predicted by Gibbs ensemble Monte Carlo simulation techniques using our two different ab initio intermolecular pair potentials. The ab initio intermolecular interaction potentials were obtained from coupled-cluster calculations. | Journal of Chemistry, Vol. 47 (5), P. 529 - 534, 2009 MONTE CARLO SIMULATION OF VAPOR - LIQUID EQUILIBRIA OF HYDROGEN USING AB INITIO INTERMOLECULAR POTENTIALS Received 6 September 2007 PHAM VAN TAT1, U. K. DEITERS2 1 Department of Chemistry, University of Dalat 2 University of Cologne, Germany abstract The vapor-liquid equilibria of pure fluid hydrogen were predicted by Gibbs ensemble Monte Carlo simulation techniques using our two different ab initio intermolecular pair potentials. The ab initio intermolecular interaction potentials were obtained from coupled-cluster calculations, using the CCSD(T) level of theory and Dunning's correlation consistent basis sets aug-cc-pVmZ (m =2, 3) [9]. The phase diagram, critical properties, thermodynamic properties, vapor pressures and orthobaric densities based on them are found to be in very good agreement with experimental data. Keywords: Vapor-liquid equilibria, Gibbs ensemble Monte Carlo simulation, ab initio potentials. I - INTRODUCTION Hydrogen and the mixture hydrogen-oxygen are used in several industrial applications. It could become the most important energy carrier of tomorrow. Liquid hydrogen, oxygen are the usual liquid fuels for rocket engines [1]. The National Aeronautics and Space Administration (NASA) is the largest user of liquid hydrogen in the world [2]. Computer simulations have become indispensable tools for studying pure fluids and fluid mixtures. One of the first attempts Nasrabad and Deiters predicted phase highpressure vapour-liquid phase equilibria of noblegas mixtures [3,4] from the global simulations using the intermolecular potentials. Leonhard and Deiters used a 5-site Morse potential to represent the pair potential of nitrogen [5] and were able to predict vapour pressures and orthobaric densities. Naicker et al. developed the 3-site pair potentials for hydrogen chloride [6]; they predicted successfully the vapour- liquid phase equilibria of hydrogen chloride with GEMC (Gibbs Ensemble Monte
