Test area method: Difference between revisions
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(New page: Related to the test volume method for the pressure (which, in turn, is related to Widom test-particle method). The surface tension of a planar interface is given by the cha...) |
Carl McBride (talk | contribs) m (Slight correction of the equation.) |
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The '''test area method''' is related to the [[test volume method]] for the calculation of the [[pressure]] (which, in turn, is related to [[Widom test-particle method]]). The [[surface tension]] of a planar [[interface]] is given by the change in [[internal energy]] <math>\Delta U</math> caused by "squeezing" the system: modifying both the length in the direction normal to the interface and the area in the plane of the interface, in such a way that the total volume is left unchanged. | |||
It can be shown that the surface tension, if the changes are small, is given by | It can be shown that the surface tension, if the changes are small, is given by | ||
<ref>[http://dx.doi.org/10.1063/1.2038827 Guy J. Gloor, George Jackson, Felipe J. Blas and Enrique de Miguel "Test-area simulation method for the direct determination of the interfacial tension of systems with continuous or discontinuous potentials", Journal of Chemical Physics '''123''' 134703 (2005)]</ref> (Eq. 60): | |||
:<math> \gamma = - \frac{ k_B T }{ \Delta {\mathcal A} } \ln \langle \exp(-\Delta U/k_B T)\rangle_0. </math> | |||
The expression parallels the one for the pressure in the [[test volume method]]; the advantages of this technique are also similar: avoidance of force calculation, easiness for discontinuous potential. | |||
==References== | ==References== | ||
<references/> | |||
[[category: computer simulation techniques]] | |||
Latest revision as of 16:21, 11 May 2009
The test area method is related to the test volume method for the calculation of the pressure (which, in turn, is related to Widom test-particle method). The surface tension of a planar interface is given by the change in internal energy caused by "squeezing" the system: modifying both the length in the direction normal to the interface and the area in the plane of the interface, in such a way that the total volume is left unchanged.
It can be shown that the surface tension, if the changes are small, is given by [1] (Eq. 60):
The expression parallels the one for the pressure in the test volume method; the advantages of this technique are also similar: avoidance of force calculation, easiness for discontinuous potential.