Abstract
Chemical potential is a fundamental thermodynamic quantity that is constant everywhere in uniform or non-uniform systems at equilibrium. Because it is not a mechanical variable, its clear interpretation is elusive and its relationship to the energetics of the molecules that make up the system has not been established. In this work, we present a link between the chemical potential and molecular energetics, using a kinetic Monte Carlo scheme. We illustrate this new interpretation using argon as a model species giving examples for adsorption on a graphite surface and for a bulk vapour-liquid equilibrium (VLE). It was found that in either an adsorbed phase or a bulk liquid phase, the chemical potential is associated with repelling molecules, despite the number of these molecules being very small. In a rarefied phase it is associated with attracting molecules. In the interfacial regions in an adsorption system or in a VLE, the energetics of the repelling and attracting molecules contribute equally to the chemical potential.
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This project is supported by the Australian Research Council (Grant # DP160103540).
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Tan, S., Loi, Q.K., Do, D.D. et al. A new interpretation of chemical potential in adsorption systems and the vapour–liquid interface. Adsorption 24, 425–430 (2018). https://doi.org/10.1007/s10450-018-9957-y
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DOI: https://doi.org/10.1007/s10450-018-9957-y