(no subject)

Please keep the list in the loop.

LAMMPS doesn't have a hard-sphere model and fix
rigid is not one.

The collision can be defined energetically or geometrically for soft-potential.

So, if you mean something like, a collision starts
when a pair of particles is less than R1 apart and continues
for some number of timesteps until they are further than R2 apart
(could have R1 = R2), then no, LAMMPS does not have a command
to tally those collisions. But you could write a fix that does it.


Thank you Steve.

For L-J particles, you could look into using a time correlation. For example, L-J collisions have well-defined peaks in power spectra of viscosity and thermal conductivity.

LAMMPS can compute these type of `system’ correlations easily, just not the expensive per-atom correlations like VACF.