Our interpretation of why the deviation from 1 arises is because the statistical mechanics analysis that leads to the g(r) = 1 -(1/N ) result for a ideal gas does not take into account that in a real system, the particles have a finite volume. Thus, the probability of finding a particle in the volume element dr j , given that another particle is in the element dr i must take into account the (excluded) volume taken up by particle i, since the two particles cannot occupy the same volume (see fig. ). As the system size increases, the ratio between the excluded volume and the total simulation volume decreases, which makes the limit approach the infinite-size limit of 1. This means that when we sample RDFs from finite-system molecular dynamics simulations, we must modify the calculation scheme to obtain the infitite-size limit of 1. For RDFs sampled in finite systems, g N lm (r), the RDF in eq. 1, the RDF is normalized to the average density of particles m, ρ m = N m /V cell . We must therefore rescale the RDF with the difference between the cell volume and the effectively accessible volume to recover the RDF as if sampled from an infinite system, g ∞ lm (r):