Figure : Acceptance probability for 3-iodotoluene as a function of the amount of NCMC relaxation. The acceptance rate shown here is analogous to that in Figure except that this test uses a fixed set of MD snapshots as a basis for move proposals, as described in the text. Overall acceptance (black line) increases dramatically up to 10000 NCMC switching steps per cycle, then increases more slowly. The black dashed line marks the acceptance probability of instantaneous MC rotations, given the same set of MD snapshots as starting points. The solid blue line denotes the acceptance probability of substantial rotations, those larger than 45 degrees, and the dashed blue line indicates the overall acceptance probability of instantaneous MC rotations from the same set of snapshots. Thus, NCMC does only modestly worse at sampling substantial rearrangements than sampling all rearrangements, whereas MC has orders of magnitude lower acceptance of substantial rearrangements.