The radial distribution function is determined by using the mean
number of particles n in a shell of width Δr at distance r, and the
mean particle density Fp in each frame, g(r) ) n(r)/(Fp4π2Δr). It has
the highest value at the radial distance equal to the particle diameter (i.e., r/D ) 1, since the smallest distance between the two in a hard
sphere particle is equal to the particle diameter). At r . D, g(r)
converges to the value of 1.