move proceeds as follows: i randomly select the
move type as an insertion or a deletion with equal probabilities; ii randomly select a particle j that acts as the target for
the swap move; iii if it is selected as an insertion move,
then a particle chosen from the ideal gas phase is placed
randomly inside the in region of particle j, or otherwise, if it
is a deletion, then a particle to be deleted is chosen randomly
from the in region of particle j; iv calculate the potential
energy difference between the initial state A and the trial
state B, EE
B
E
A; and v accept this move with the
following set of acceptance probabilities