Hard particles with cohesion

Hi,

Could you please explain how the hard particles (Event-driven) approach is implemented in LIGGGHTS? I couldn't find the details in the documentary and source code.

In the event-driven approach, usually the overlap of the particles doesn't happen, and the cohesion models are dependent on the overlap. So how can we use the cohesion models in hard particles?

I request to please provide the relationship between cohesion energy and surface energy used in literature in JKR models?

Thanks and regards
David