Static and dynamical properties of a supercooled liquid confined in a pore

Abstract

We present the results of a Molecular Dynamics computer simulation of a binary Lennard-Jones liquid confined in a narrow pore. The surface of the pore has an amorphous structure similar to that of the confined liquid. We find that the static properties of the liquid are not affected by the confinement, while the dynamics changes dramatically. By investigating the time and temperature dependence of the intermediate scattering function we show that the dynamics of the particles close to the center of the tube is similar to the one in the bulk, whereas the characteristic relaxation time tau_q(T,rho) of the intermediate scattering function at wavevector q and distance rho from the axis of the pore increases continuously when approaching the wall, leading to an apparent divergence in the vicinity of the wall. This effect is seen for intermediate temperatures down to temperatures close to the glass transition. The rho-dependence of tau_q(T,rho) can be described by an empirical law of the form tau_q(T,ρ)=f_q(T) exp [Delta_q/(rho_p-rho)], where Delta_q and ρ_q are constants, and f_q(T) is the only parameter which shows a significant temperature dependence.