2003/10/07 by A. Maciolek, A. Drzewinski, P. Bryk
Physics and Astronomy · #cond-mat.stat-mech
paper · pdf · doi:10.1063/1.1635807
published as J. Chem. Phys. 120, 1921 (2004) · 48 pages, 12 figures
arxiv created 2003/10/07 · arxiv updated 2009/12/01
The solvation force of a simple fluid confined between identical planar walls is studied in two model systems with short ranged fluid-fluid interactions and long ranged wall-fluid potentials decaying as -Az-p, z→ ∞, for various values of p. Results for the Ising spins system are obtained in two dimensions at vanishing bulk magnetic field h=0 by means of the density-matrix renormalization-group method; results for the truncated Lennard-Jones (LJ) fluid are obtained within the nonlocal density functional theory. At low temperatures the solvation force fsolv for the Ising film is repulsive and decays for large wall separations L in the same fashion as the boundary field fsolv∼ L-p, whereas for temperatures larger than the bulk critical temperature fsolv is attractive and the asymptotic decay is fsolv∼ L-(p+1). For the LJ fluid system fsolv is always repulsive away from the critical region and decays for large L with the the same power law as the wall-fluid potential. We discuss the influence of the critical Casimir effect and of capillary condensation on the behaviour of the solvation force.