Critical activity of the hard-sphere lattice gas on the body-centred cubic lattice

This is the first Monte Carlo study of the hard-sphere lattice gas with nearest neighbour exclusion on the body-centred cubic lattice. We estimate the critical activity to be 0.7223±0.0003. This result confirms that there is a re-entrant phase transition of an antiferromagnetic Ising model in an external field and a Blume-Emery-Griffiths model on the body-centred cubic lattice.