Citation:
Parry, A.O., Rascón, C. (2019). Microscopic determination of correlations in the fluid interfacial region in the presence of liquid-gas asymmetry. Physical Review E, 100 (5) 052801
xmlui.dri2xhtml.METS-1.0.item-contributor-funder:
Engineering and Physical Sciences Research Council (EPSRC) Ministerio de Economía y Competitividad (España)
Sponsor:
A.O.P. acknowledges the EPSRC, UK for Grant No.
EP/L020564/1 (multiscale analysis of complex interfacial
phenomena). C.R. acknowledges the support from Grant No.
PGC2018-096606-B-I00 (MCIU/AEI/FEDER, UE).
In a recent article, we showed how the properties of the density-density correlation function and its integral,
the local structure factor, in the fluid interfacial region, in systems with short-ranged forces, can be understood
microscopically by consideringIn a recent article, we showed how the properties of the density-density correlation function and its integral,
the local structure factor, in the fluid interfacial region, in systems with short-ranged forces, can be understood
microscopically by considering the resonances of the local structure factor [A. O. Parry and C. Rascón, Nat.
Phys. 15, 287 (2019)]. Here, we illustrate, using mean-field square-gradient theory and the more microscopic
Sullivan density functional model, and how this approach generalizes when there is liquid-gas asymmetry, i.e.,
when the bulk correlation lengths of the coexisting liquid and gas phases are different. In particular, we are
able to express the correlation function exactly as a simple average of contributions arising from two effective
Ising-symmetric systems referred to as the symmetric gas and symmetric liquid. When combined with our earlier
results, this generates analytical approximations for the correlation function and the local structure factor, which
are near indistinguishable from the numerical solution to the Ornstein-Zernike equations over the whole range of
wave vectors. Our results highlight how asymmetry affects the correlation function structure and describes the
crossover from a long-ranged Goldstone mode to short-ranged properties determined by the local density as the
wave vector increases.[+][-]