Nudged Elastic Band calculation of the binding potential for liquids at interfaces

Buller O, Tewes W, Archer A, Heuer A, Thiele U, Gurevich S

Abstract

The wetting behavior of a liquid on solid substrates is governed by the nature of the effective interaction between the liquid-gas and the solid-liquid interfaces, which is described by the binding or wetting potentialg(h) which is an excess free energy per unit area that depends on the liquid film heighth. Given a microscopic theory for the liquid, to determineg(h), one must calculate the free energy for liquid films of any given value ofh, i.e., one needs to create and analyze out-of-equilibrium states, since at equilibrium there is a unique value ofh, specified by the temperature and chemical potential of the surrounding gas. Here we introduce a Nudged Elastic Band (NEB) approach to calculateg(h) and illustrate the method by applying it in conjunction with a microscopic lattice density functional theory for the liquid. We also show that the NEB results are identical to those obtained with an established method based on using a fictitious additional potential to stabilize the non-equilibrium states. The advantages of the NEB approach are discussed.