Free energy of formation of small clusters using the BAR method and MD simulations

Abstract

Accurate free energy difference calculations based on molecular dynamics (MD) simulations are still a computational challenge. In this study, the free energy differences between successive cluster sizes of SPC/E-water are calculated using the Bennett acceptance ratio (BAR) method at three temperatures, T = 220K, 240K, and 260K. The simulation results show that the free energy differences of the small clusters scale nicely with the inverse of TcT-1, using the appropriate critical temperature, Tc, of SPC/E-water of 625 K.