Calculation of phase coexistence properties and surface tensions of n-alkanes with grand-canonical transition-matrix monte carlo simulation and finite-size scaling.
Grand-canonical transition-matrix Monte Carlo is combined with configurational-bias and expanded ensemble Monte Carlo techniques to obtain saturated densities and vapor pressures of select n-alkanes. Surface tension values for butane, hexane, and octane are also computed via the finite-size scaling method of Binder. The exponential-6 model of Errington and Panagiotopoulos is used to describe the molecular interactions. The effect of the number of configurational-bias trial conformations on the efficiency of phase equilibra calculations is studied. We find that a broad range of trial conformation numbers give reasonable performance, with the optimal value increasing with decreasing temperature for a fixed chain length. Phase coexistence properties are in good agreement with literature values and are obtained with very reasonable computing resources. Similar to other recently developed n-alkane force fields, the exponential-6 model overestimates the surface tension relative to experimental values. Statistical uncertainties for coexistence properties obtained with the current approach are relatively small compared to existing methods.
Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA.
Jayant K
JK
Singh
Jeffrey R
JR
Errington
D000473:Alkanes / Q000737:chemistry*; D003198:Computer Simulation; D008567:Membranes, Artificial; D008956:Models, Chemical; D009010:Monte Carlo Method; D044367:Phase Transition; D013500:Surface Tension
D000473:Alkanes; D008567:Membranes, Artificial