Phase Diagram of a Physisorbed Krypton Monolayer on Graphite Using an Ellipsometric Technique

Choi, B. I.; Nham, H. S.; Youn, Hwa Shik

doi:10.3938/jkps.53.3262

Cited by 10 publications

(7 citation statements)

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“…The distortions of the spacer structure can only decrease these barriers and thus do not affect this qualitative result. It should also be noted that, though commensurate argon layers on graphite − and lateral surfaces of carbon nanotubes are well studied, there is no evidence for symmetry distortions.…”

Section: Methodsmentioning

confidence: 99%

Structure, Energetic and Tribological Properties, and Possible Applications in Nanoelectromechanical Systems of Argon-Separated Double-Layer Graphene

et al. 2013

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The possibility to control the commensurability and distance between graphene layers separated by a dielectric spacer is considered by the example of a heterostructure 2 consisting of double-layer graphene separated by atomic layers of argon. Van der Waals corrected density functional theory (DFT-D) is applied to study structural, energetic and tribological characteristics of this heterostructure. It is found that in the ground state, monolayer and bilayer argon spacers are incommensurate with the graphene layers, whereas submonolayer argon spacers which are commensurate with the graphene layers can exist only as metastable states. The calculations show that this incommensurability provides negligibly small static friction for relative motion of argon-separated graphene layers and, therefore, such a heterostructure holds great promise for the use in nanoelectromechanical systems. A scheme and operational principles of the nanorelay based on the revealed tribological properties of the heterostructure are proposed. 1.

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Section: Methodsmentioning

confidence: 99%

Structure, Energetic and Tribological Properties, and Possible Applications in Nanoelectromechanical Systems of Argon-Separated Double-Layer Graphene

et al. 2013

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“…Ne 0.2801 [41] 33.921 [41] 13.6 [42] 15.8 [42] Ar 0.33952 [41] 116.79 [41] 47.2 [43] 58 [43] Kr 0.3685 [41] 164.4 [41] 84.8 [4] 86 [4] Xe 0.3901 [41] 227.55 [41] 100 [4] 117 [4] (*) experimental values…”

Section: Fluid-fluid Potentialmentioning

confidence: 99%

The role of adsorbate size on adsorption of Ne and Xe on graphite

Prasetyo

Loi

Tan

et al. 2018

Journal of Colloid and Interface Science

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We have carried out an extensive grand canonical Monte Carlo simulation to investigate the adsorption of neon and xenon on graphite. The adsorbate collision diameters of neon and xenon are smaller and greater respectively, than the commensurate graphite lattice spacing λ=3×3R30 of 0.426 nm. Simulated isotherms and isosteric heats were obtained using a graphite model that has been shown to describe successfully the adsorbate transitions for krypton, methane and nitrogen by Prasetyo et al. (2017), which have collision diameters close to λ. Neon does not exhibit commensurate (C) packing because the gain in the intermolecular potential interactions in the incommensurate (IC) packing when molecules move away from carbon hexagon centres, does not compensate for the increase in the solid-fluid potential energy. Xenon, on the other hand, exhibits IC packing because its molecular size is greater than λ. Nevertheless, at a sufficiently high chemical potential, the first layer of xenon changes from the IC to C packing (in contrast to what is observed for krypton, nitrogen and methane). This transition occurs because the decrease in the xenon intermolecular interactions is sufficiently compensated by the increase in the solid-fluid interaction, and the increase in the fluid-fluid interactions between molecules in the first layer and those in the second layer. This finding is supported by the X-ray diffraction study by Mowforth et al. (1986) and Morishige et al. (1990).

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“…The liquid–solid and the fluid–solid transitions have received particular attention. Experimentally, the phase transition is observed using calorimetric measurements of the heat capacity change in the adsorbed phase, − the differential heat of adsorption, , and the adsorption isotherm analysis. − Some investigations of the 2D transitions are based on the neutron diffraction technique and X-ray scattering. , A description of other scattering and resonance techniques applied to the analysis of adsorbed molecular layers can be found elsewhere …”

Section: Introductionmentioning

confidence: 99%

Fluid–Solid Phase Transition in Molecular Layers Adsorbed on a Smooth Surface: A New Insight from Molecular Simulations

Ustinov

2018

J. Phys. Chem. C

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Two-dimensional (2D) phase transitions in molecular layers adsorbed on various surfaces have attracted much research attention over the past decades. Special attention is paid to the solidification/melting transition using methods based on molecular simulation techniques. The main research interest is focused on parameters of the liquid–solid or fluid–solid transitions; that is, the pressure, the chemical potential, and the density change. It is implied that the liquid and solid phases coexist like vapor and liquid with a flat interface, and the transition occurs simply via gradual increase of the solid fraction at a constant pressure. However, visualization of the transition based on molecular simulation in a canonical Monte Carlo method in a relatively large simulation cell has shown that the liquid and solid phases form islands in the liquid or “lakes” in the solid of arbitrary size and shape without a distinct interface. For this reason, the aim of this study was a detailed analysis of the 2D phase transition with the emphasis on the properties of the intermediate state between the pure liquid (fluid) and the crystal. Thermodynamically, the transition phase behaves like a two-phase system: when the density changes over a certain range at a specified temperature, the tangential pressure is nearly constant. However, no energy barrier was observed at the transition from the pure liquid or fluid to the intermediate phase. The absence of the van der Waals loop provides a very efficient way to determine parameters of the 2D liquid/fluid–solid transition and the chemical potential of the crystalline phase by a thermodynamic integration or direct evaluation with the kinetic Monte Carlo simulation in a sufficiently large simulation cell. The advantage of this way is that it makes the liquid–solid transition reversible without resorting to any special procedures.

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Phase Diagram of a Physisorbed Krypton Monolayer on Graphite Using an Ellipsometric Technique

Cited by 10 publications

References 0 publications

Structure, Energetic and Tribological Properties, and Possible Applications in Nanoelectromechanical Systems of Argon-Separated Double-Layer Graphene

Structure, Energetic and Tribological Properties, and Possible Applications in Nanoelectromechanical Systems of Argon-Separated Double-Layer Graphene

The role of adsorbate size on adsorption of Ne and Xe on graphite

Fluid–Solid Phase Transition in Molecular Layers Adsorbed on a Smooth Surface: A New Insight from Molecular Simulations

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