Optimized atomic Lennard-Jones 6–12 parameters for simulating pVT properties of a realistic polymethylene melt

From the comparison of experimental low-pressure pVT data for a short alkane with the results of Monte Carlo simulations in the NpT ensemble of an atomistically detailed model of polymethylene (PM) with explicit hydrogens, we have obtained Lennard-Jones parameters that allow accurate prediction of pVT behavior for liquid long-chain alkanes at high pressure. The parameters were obtained from the Slater–Kirkwood formula and fitted to the experimental density of n-pentane at 0.1 MPa; they faithfully reproduce experimental data for chains up to C23H48 (n-tricosane) and pressures up to 100 MPa over a wide temperature interval.