ReaxFF \ fix MSST

Hey dear all !

I’m experimenting with the relatively new feature of msst in lammps.
I’d like to simulate a shock wave passing through some crystal , say, a TNT cubic slab.

Although i’ve read the 2003 paper by Reed, and the manual part for the fix msst, I’m still not sure about this method.

Specificaly, how should I choose the q value (mass like parameter) for my system ?

Is there any example \ manual for simulations with msst together with reaxff ?

Thanks !

Maybe Aidan has some advice on this. I would just
try different Q values and see how the code performs
by monitoring the output.


If Q is set too small, the barostat dynamics can become unstable. If it is
set too large, the simulation will have to be run for an excessively long
time. So, the right strategy is to find the smallest Q that does not cause
spurious behavior. This can be found be trying out different values and
critically examining the results.

Also you must specify the Piston Velocity, I never saw what equations they use to model the passing of the wave (Looked at the Lammps source code) my guess is are the Rankie - Hugonitot. Who at the same time using modifications can become the quasi - isentropic scheme (not sure about that). =) I wouid really like the the pressure vs volume condition change on your simulation. A Graph help alot to understad what your doing .

Best regards
Oscar G.