School of Chemistry F11, University of Sydney, NSW 2006 Australia.
J. Chem.\ Phys.\ 107, 3230-3238 (1997)
Abstract
Grand canonical simulations, (specified chemical potential),
are performed with a fixed number of particles
by coupling variations in the system size
to the instantaneous chemical potential
determined by virtual test particle methods.
This is a modified form of the pseudo grand canonical method of
Mehta and Kofke [Mol. Phys. 86, 139 (1995)].
For dense fluids the method has the advantage
of allowing the chemical potential to be specified
without inserting particles,
and is particularly suited to confined fluids,
allowing the geometry to be changed at constant chemical potential.
For the test particle determination of the chemical potential
a preferential cell sampling method is developed
that improves the excluded volume map sampling
of Dietrick et al. [J. Chem. Phys. 90, 2370 (1989)].
It is several orders of magnitude more efficient than crude Monte Carlo
sampling, and 4--40 times more efficient than restricted umbrella sampling.
The methods are tested on Lennard-Jones fluids,
in the bulk at reduced densities up to 0.95,
and confined between two planar walls.
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