RT Journal Article
T1 Correlation-function structure in square-gradient models of the liquid-gas interface: Exact results and reliable approximations
A1 Parry, A. O.
A1 Rascón, Carlos
AB In a recent article, we described how the microscopic structure of density-density correlations in the fluid interfacial region, for systems with short-ranged forces, can be understood by considering the resonances of the local structure factor occurring at specific parallel wave vectors q [Nat. Phys. 15, 287 (2019)]. Here we investigatethis further by comparing approximations for the local structure factor and pair correlation function against three new examples of analytically solvable models within square-gradient theory. Our analysis further demonstrates that these approximations describe the pair correlation function and structure factor across the whole spectrum ofwave vectors, encapsulating the crossover from the Goldstone mode divergence (at small q) to bulklike behavior (at larger q). As shown, these approximations are exact for some square-gradient model potentials and never more than a few percent inaccurate for the others. Additionally, we show that they describe very accurately the correlation function structure for a model describing an interface near a tricritical point. In this case, there are no analytical solutions for the correlation functions, but the approximations are nearly indistinguishable from the numerical solutions of the Ornstein-Zernike equation.
PB American Physical Society
SN 2470-0053 (online)
SN 2470-0045 (print)
YR 2019
FD 2019-08
LK https://hdl.handle.net/10016/28740
UL https://hdl.handle.net/10016/28740
LA eng
NO A.O.P. acknowledges the EPSRC, UK, for Grant No. EP/L020564/1 (Multiscale Analysis of Complex Interfacial Phenomena). C.R. acknowledges the support of Grant No. PGC2018-096606-B-I00 (MCIU/AEI/FEDER, UE).
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RD 4 may. 2024