Figure shows the probability of state as a function of time for MD/NCMC simulation with flip moves for ligand 1. The moves still sample from Boltzmann distribution and the population converges to the ideal 50/50 population distribution. The number of moves accepted per million force evaluations ( 30 ± 2 ) and transitions per million force evaluations (28.4 ± 0.4) are very close in value, whereas for our previous random torsional move proposals, about half of the moves resulted in actual transitions (29 ± 2 moves accepted per million force evaluations and 15.72 ± 0.08 transitions per million force evaluations). The efficiency of flip moves is also evident from the shorter convergence time (∼2 ns or 1000 iterations) compared to random torsional moves (∼5 ns or 2500 iterations from Figure ).