PROPERTIES OF THE SQUARE-WELL FLUID OF VARIABLE WIDTH .4. MOLECULAR-DYNAMICS TEST OF THE VANDERWAALS AND LONG-RANGE APPROXIMATIONS

Simulation results for a square-well (SW) fluid of range lambda = 3 are presented and used to test the long-range (LR) theory recently developed for SW systems. The discontinuous molecular dynamics methods was used to obtain values of internal energies, pressures and orthobaric densities. The predictions of the second-order LR theory are in excellent agreement with the simulated results, showing that the LR approximation is highly accurate for ranges lambda greater-than-or-equal-to 3. The accuracy of the van der Waals, mean-field and LR approximations is established in terms of the temperature of the system and the range of the well.