Naslov
Surface melting of methane and methane film on magnesium oxide

Autori
Klipa, Nenad ; Bilalbegović, Goranka

Izvornik
Surface Science (0039-6028) 477 (2001), 2-3; 243-249

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Construction and use of effective interatomic interactions; Equilibrium thermodynamics and statistical mechanics; Dielectric phenomena; Surface melting; Wetting; Magnesium oxides; Alkanes; Solid-liquid interfaces

Sažetak
Experiments on surface melting of several organic materials have shown contradictory results. We study the Van der Waals interactions between interfaces in surface melting of the bulk CH_4 and interfacial melting of the CH_4 film on the MgO substrate. This analysis is based on the theory of Dzyaloshinskii, Lifshitz, and Pitaevskii for dispersion forces in materials characterized by the frequency dependent dielectric functions. These functions for magnesium oxide and methane are obtained from optical data using an oscillator model of the dielectric response. The results show that a repulsive interaction between the solid-liquid and liquid-vapor interfaces exists for the bulk methane. We also found that the van der Waals forces between two solid-liquid interfaces are attractive for the CH_4 film on the MgO substrate. This implies that the van der Waals forces induce the presence of complete surface melting for the bulk methane and the absence of interfacial melting for CH_4 on the MgO substrate.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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