Communications: Evidence for the Role of Fluctuations in the Thermodynamics of Nanoscale Drops and the Implications in Computations of the Surface Tension

0354874 - ÚCHP 2011 RIV US eng J - Journal Article
Sampayo, J.G. - Malijevský, Alexandr - Müeller, E.A. - de Miguel, E. - Jackson, G.
Communications: Evidence for the Role of Fluctuations in the Thermodynamics of Nanoscale Drops and the Implications in Computations of the Surface Tension.
Journal of Chemical Physics. Roč. 132, č. 14 (2010), , 141101 -1-4. ISSN 0021-9606. E-ISSN 1089-7690
R&D Projects: GA AV ČR IAA200760905; GA AV ČR IAA400720710
Grant - others:DGI(ES) FIS2007–66079–C0202; JA(ES) P07-FQM02884; EPSRC(GB) EP/E016340
Institutional research plan: CEZ:AV0Z40720504
Keywords : drops * free energy * molecular dynamics method
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.920, year: 2010

Test-area deformations are used to analyze vapor-liquid interfaces of Lennard-Jones particles by molecular dynamics simulation. For planar vapor-liquid interfaces the change in free energy is captured by the average of the corresponding change in energy, the leading-order contribution. This is consistent with the commonly used mechanical pressure-tensor route for the surface tension. By contrast for liquid drops, one finds a large second-order contribution associated with fluctuations in energy. Both the first- and second-order terms make comparable contributions, invalidating the mechanical relation for the surface tension of small drops. The latter is seen to increase above the planar value for drop radii of 8 particle diameters, followed by an apparent weak maximum and slow decay to the planar limit, consistent with a small negative Tolman length.
Permanent Link: http://hdl.handle.net/11104/0193780