Pressure, dynamics, and structure of a simple particle system confined in a soft nanopore

The formation and dynamics of long living metastable structures, the pressure tensor and diffusion properties of a simple particle system confined by a (infinite) nanopore with rectangular cross section is investigated using molecular dynamics simulation. The system is characterized by a short range and radially symmetric interparticle (SHRAT, Lennard-Jones type) potential between mass points. The lateral confinement is considered as soft, repulsive, and unstructured. Periodic images are used in the longitudinal direction. Spontaneous condensation is observed as well as merging of patterns induced by the confinement. Structures, pressure, and diffusion coefficient are found depending on both the pore's lateral aspect ratio and its absolute width, temperature and density. Theoretical expectations are rarely available but tested against the simulation results under appropriate conditions. (C) 2004 Elsevier B.V. All rights reserved.