Hi all,

I have some questions about data collection in MD. According to some literature, it seems that the MD consists of two stage, the first one is equilibration, the second one is data collection. Does this mean that we have to run simulation twice with different time step and different simulation time while keep all the other parameters same? How can we determine the time step for data collection if the time step for equilibration is 1 fs? Some paper suggested  4 fs, some paper suggested 10 fs. But neither works for me. The sofeware aborted calculation and said "an unphisical integrating step (>100 angstroms) has been detected, try reducing the time step or relaxing the structure first." I tried 2 fs, it worked, but isn't this too short?

Any one has any suggestion?

Thank you.

Jingjing