  We have studied the temperature dependence of the solubility of nitrogen in
methane, ethane, and mixtures of methane and ethane using vapor-liquid
equilibrium simulations of binary and ternary mixtures of nitrogen, methane and
ethane for a range of temperatures between 90K and 110K at a pressure of 1.5
atm, thermodynamic conditions that may exist on the Saturn's giant moon, Titan.
We find that --(i) the solubility of nitrogen in both methane and ethane
decreases with increasing temperature; (ii) the solubility of nitrogen in
methane is much larger compared to that in ethane at low temperatures, (iii)
solubility of nitrogen in a ternary mixture of methane, ethane, and nitrogen
increases upon increasing mole-fraction of methane. Our results are in
quantitative agreement with the recent experimental measurement of the
solubility of nitrogen in methane, ethane, and a mixture of methane and ethane.
Furthermore, we find a strong temperature-dependent surface adsorption of
nitrogen at the nitrogen-hydrocarbon interface, previously unknown. We have
also investigated surface tension of the gas-liquid interface and find that it
decreases upon decreasing temperature. Moreover, we find that the interfacial
layer of adsorbed nitrogen and ethane show a preferential orientational
ordering at the interface.
