a) Pressure P in [Pa] against filling factor φ. The ten thin solid lines show the results for the initial BCCA clusters with different initial random numbers and thick solid line shows the arithmetic average of the ten runs. b) Pressure P in [Pa] against filling factor φ. Same as the thick solid line in a) plotted with a dotted line of Eq. (25). The parameters are N = 16   384, C_v = 3 × 10^-7, k_n = 0.01, and ξ_crit = 8   Å.