Scaling of correlation functions near capillary condensation Articles uri icon

publication date

  • January 2011

start page

  • 1015

end page

  • 1027

issue

  • 7-10

volume

  • 109

International Standard Serial Number (ISSN)

  • 0026-8976

Electronic International Standard Serial Number (EISSN)

  • 1362-3028

abstract

  • Special Issue: A Special Issue in Honour of Robert Evans. [Resumen]. We study the influence of wetting films on (density&-density) correlations for a fluid in a slit-like geometry near capillary condensation. We show that, for systems with short-ranged forces, the interaction between the wetting films strongly enhances the amplitude of the exponential decay of correlations and, unlike the interfacial roughness, is independent of a high-momentum cut-off. The correlation function shows scaling behaviour near condensation arising from the equality of two characteristic length scales: the parallel correlation length (associated with the complete wetting films) and a length scale related to the non-local interaction between the wetting films on either side of the slit. We introduce a dimensionless amplitude ratio associated with the decay of correlations which allows us to distinguish between local and non-local effective Hamiltonian theories. Only the latter is fully consistent with microscopic density functional descriptions of correlation functions. The influence of long-ranged intermolecular forces and fluctuation effects in two dimensions is also discussed.

keywords

  • capillary condensation; ; wetting; ; correlation function; ; effective hamiltonian; ; scaling