Question about hyperdynamics/bond boost theory
I'm reading the configuration options on http://theory.cm.utexas.edu/eon/hyperdynamics.html and just want to make sure I understand them correctly. I'm very new to hyperdynamics, though I've done a lot of molecular dynamics simulations previously.
I've had a read of the two referenced papers, and my understanding is the two most important parameters are:
bb_dvmax: the magnitude of the bond-boost bias potential
bb_stretch_threshold: defining the bond-boost dividing surface
If I understand correctly, bb_dvmax should be of the order of the lowest activation barrier for any infrequent events you're interested in: is this a strict upper bound, or would you still get useful results as long as the number is of the correct order? The Voter paper seemed to suggest the latter, but I'm not sure how the simulation 'breaks' if your bias potential is too large. How does one go about optimising these parameters given the output EON makes available? Do you just keep making them larger until you observe unrealistic behaviour? Or do you need to manually enumerate each possible 'event', find its transition state, activation barrier, bond lengths, etc., and use those? (For my system this might be quite difficult to do every combination of events, though I know roughly what a 'typical' event will be like.)
Also, is there any danger in using a too-large bb_rcut? Presumably you want to set bb_rcut to just include nearest neighbours?
Finally, how does one use EON to find the connection between statistical MD time and 'real' time?
Many thanks for your help.
With best regards,