CONTINUUM-CONFIGURATIONAL-BIAS MONTE-CARLO SIMULATIONS OF LONG-CHAIN ALKANES

The recently introduced continuum-configurational-bias method for Mont e Carlo simulations is employed for the generation of large samples of many-chain n-alkane systems with chain lengths of 11, 24 and 71 carbo n atoms. The simulations are used to investigate the adequacy of repre senting methylene groups as united-atom Lennard-Jones interaction site s, and to test the configurational-bias approach against traditional r andom moves and reptation moves with respect to the computational effi ciency and numerical stability of the calculated ensemble averages. Th e results of simulations with constant pressure, temperature, and numb er of molecules demonstrate that, with an appropriate mixture of diffe rent types of Monte Carlo moves, an efficient and stable strategy can be obtained. Adjustment of the Lennard-Jones parameters leads to resul ts that are in good agreement with experimental data for the density o f liquid alkanes over a large temperature interval.