Equation of State of the Hard-Disk Fluid from Approximate Integral Equations

The Percus–Yevick, hypernetted‐chain, and “pressure‐consistent' integral equations have been solved, using numerical Hankel transforms, for a fluid of two‐dimensional hard cores. The thermodynamic quantities obtained from these solutions are presented and compared among themselves and with the results of other theories; a comparison of computed pair distribution functions $g$ with a Monte Carlo $g$ is also presented. The Percus–Yevick equation is found to give the best over‐all results.