Abstract
The aim of this paper is to study the effects of temperature on the state of the adsorbed argon on an uniform graphite surface. We applied the kinetic Monte Carlo scheme to simulate adsorption over a very wide range of temperature, which allows us to model the vapor–solid, the vapor–liquid and the order–disorder transition of the monolayer. The main distinction of our methodology is that it accounts for the lattice constant change with loading in the case of formation of an ordered molecular layer by appropriately changing the simulation box size. To do this we enforced the equality of the tangential pressures obtained by the virial and thermodynamic routes, which corresponds to the minimum Helmholtz free energy of a system at a given number of molecules and volume. This criterion is a consequence of the Gibbs–Duhem equation. A significant result obtained by application of the new simulation method was a sharp contraction of the monolayer just after its completion and the onset of the second layer. It manifests itself in an additional heat release. We re-determined the 2D-melting and 2D-critical temperatures of the molecular layer of argon. We also analyzed the order–disorder transition above the 2D-melting and showed that it could occur at some temperatures above the 2D-critical temperature. In this case, a hexagonal lattice appears at a sufficiently large tangential pressure. The effects of loading on the lattice constant, the 2D-critical temperature of the order–disorder transition and the differential heat of adsorption are thoroughly discussed.
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Abraham, F.: The phases of two-dimensional matter, their transitions, and solid-state stability: a perspective via computer simulation of simple atomic systems. Phys. Rep. 80, 339–374 (1981)
D’Amico, K.L., Bohr, J., Moncton, D.E., Gibbs, D.: Melting and orientational epitaxy in argon and xenon monolayers on graphite. Phys. Rev. B 41, 4368–4376 (1990)
Day, P., Lysek, M., Madrid, M., Goodstein, D.: Phase transitions in argon films. Phys. Rev. B 47, 10716–10726 (1993)
Do, D.D., Nicholson, D., Do, H.D.: On the anatomy of the adsorption heat versus loading as a function of temperature and adsorbate for a graphitic surface. J. Colloid Interface Sci. 325, 7–22 (2008)
Fan, Ch., Birkett, G., Do, D.D.: Effects of surface mediation on the adsorption isotherm and heat of adsorption of argon on graphitized thermal carbon black. J. Colloid Interface Sci. 342, 485–492 (2010)
Fan, Ch., Razak, M.A., Do, D.D., Nicholson, D.: On the identification of the sharp spike in the heat curve for argon, nitrogen, and methane adsorption on graphite: reconciliation between computer simulations and experiments. J. Phys. Chem. C 116, 953–962 (2012)
Flenner, E., Etters, R.D.: Behavior of partial monolayers of argon adlayers deposited on graphite. Phys. Rev. Lett. 88, 106101 (2002)
Flenner, E., Etters, R.D.: Properties of argon adlayers deposited on graphite from Monte Carlo calculations. Phys. Rev. B 73, 125419 (2006)
Golebiowska, M., Firley, L., Kuchta, B., Fabianski, R.: Structural transformations of nitrogen adsorbed on graphite: Monte Carlo studies of spatial heterogeneity in multilayer system. J. Chem. Phys. 130, 204703 (2009)
Grillet, Y., Rouquerol, F., Rouquerol, J.: Two-dimensional freezing of nitrogen or argon on differently graphitized carbons. J. Colloid Interface Sci. 70, 239–244 (1979)
Hansen, J.P., McDonald, I.R.: Theory of Simple Liquids, 2nd edn. Academic Press, London (1986)
Irving, J.H., Kirkwood, J.G.: The statistical mechanical theory of transport processes. IV. The equations of hydrodynamics. J. Chem. Phys. 18, 817 (1950)
Kuchta, B., Etters, R.D.: Calculated properties of monolayer and multilayer N2 on graphite. Phys. Rev. B 36, 3400–3406 (1987)
Larese, J.Z., Zhang, Q.M.: Phase transitions of argon multilayer films on graphite: evolution from multilayer film to bulk solid. Phys. Rev. B 51, 17023–17027 (1995)
Migone, A.D., Li, Z.R., Chan, M.H.W.: Melting transition of submonolayer Ar adsorbed on graphite. Phys. Rev. Lett. 53, 810–813 (1984)
Morrison, J.A.: Calorimetry in the study of physical adsorption. Pure Appl. Chem. 59, 7–14 (1987)
Nguyen, V.T., Do, D.D., Nicholson, D.: On the heat of adsorption at layering transitions in adsorption of noble gases and nitrogen on graphite. J. Phys. Chem. C 114, 22171–22180 (2010)
Nicholson, D., Parsonage, N.G.: Simulation studies of the fluid–solid monolayer transition in argon adsorbed on graphite at 77.5 K. J. Chem. Soc. Faraday Trans. 2. 82, 1657–1667 (1986)
Nicholson, D., Rowley, L.A., Parsonage, N.G.: Monte Carlo calculations for the interaction of 12-6 argon at 80 K with graphite in the region of monolayer adsorption. J. Phys. 38, 69–75 (1977)
Pettersen, M.S., Lysek, M.J., Goodstein, D.L.: Melting in monolayer adsorbed films. Phys. Rev. B 40, 4938–4946 (1989)
Rouquerol, J., Partyka, S., Rouquerol, F.: Calorimetric evidence for bidimensional phase change in the monolayer of nitrogen or argon adsorbed on graphite at 77 K. J. Chem. Soc. Faraday Trans. I 73, 306–314 (1977)
Strandburg, K.J.: Two-dimensional melting. Rev. Mod. Phys. 60, 161 (1988)
Thomy, A., Duval, X.: Adsorption de molecules simples sur graphite. J. Chim. Phys. 67, 286–290 (1970)
Ustinov, E.A., Do, D.D.: Two-dimensional order–disorder transition of argon monolayer adsorbed on graphitized carbon black: kinetic Monte Carlo method. J. Chem. Phys. 136, 134702 (2012a)
Ustinov, E.A., Do, D.D.: Thermodynamic analysis of ordered and disordered monolayer of argon adsorbed on graphite. Langmuir 28, 9543–9553 (2012b)
Ustinov, E.A., Do, D.D.: Application of kinetic Monte Carlo method to equilibrium systems: vapor–liquid equilibria. J. Colloid Interface Sci. 366, 216–223 (2012c)
Ustinov, E.A., Do, D.D.: Simulation of gas adsorption on a surface and in slit pores with grand canonical and canonical kinetic Monte Carlo methods. Phys. Chem. Chem. Phys. 14, 11112–11118 (2012d)
Wongkoblap, A., Do, D.D.: Explanation of the unusual peak of calorimetric heat in the adsorption of nitrogen, argon and methane on graphitized thermal carbon black. Phys. Chem. Chem. Phys. 10, 1106–1113 (2007)
Zhu, D.M., Dash, J.G.: Surface melting and roughening of adsorbed argon films. Phys. Rev. Lett. 57, 2959–2962 (1986)
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This work is supported by Russian Foundation for Basic Research (project No 11-03-00129-a). Support from the Australian Research Council is also acknowledged.
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Ustinov, E.A., Do, D.D. Effects of melting and ordering on the isosteric heat and monolayer density of argon adsorption on graphite. Adsorption 19, 291–304 (2013). https://doi.org/10.1007/s10450-012-9452-9
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DOI: https://doi.org/10.1007/s10450-012-9452-9