Molecular dynamics of interfaces in opposing fields

Equilibrium binary liquid mixture below its upper critical consolute temper ature, confined between opposing walls, is investigated by molecular dynami cs simulations. The wall potentials are chosen strong enough to ensure that both walls are wet and therefore the interface is delocalized. The interfa cial widths (W) are determined from density profiles and from order paramet er profiles for a series of wall to wall distances (D). Early saturation of the width with increasing D is found already for D similar to 20 sigma and data at the other end are consistent with the theoretical prediction of li near dependence of W-2 on D. Also, the error function complement is found s lightly superior to the hyperbolic tangent, on the basis of a new test of c onsistency proposed. (C) 2001 American Institute of Physics.