Hi,
I've been doing test MD runs on alpha quartz using various potentials. I have been testing out the BKS, ReaxFF and COMB potentials. I am quite interested in the ReaxFF and COMB potentials due to their charge dynamically being able to change. My test runs involved 243 atoms run at 298K with 1fs timestep. I just wanted to ask whether my simulations are being run correctly because using ReaxFF and COMB takes much longer and I wanted to check this was valid. My BKS run took 2 hours 8 mins. My COMB run took 18 hours 28 minutes and ReaxFF took 46 hours 35 minutes, both without charge determination (I used the BKS fixed charges just to test how long it took). Is this something to be expected from the COMB and ReaxFF potentials.
COMB input script (ReaxFF and BKS scripts are v. similar):
# Alpha quartz MD run using COMB potential