Viscosity or damp factor of langevin


I am doing the coarse-grained simulation of intrinsically disordered proteins. I am using CG models like HPS and KH to simulate different IDPs. I am doing an implicit solvent simulation and given all the required interactions in the forcefield. It is running and gives a result close to the paper result mentioned.

But the problem is there some new CG models came with the same interactions, but they are running at different Langevin damp factor. So I am confused about how the author decided Langevin damp factor for their model.

example: HPS and KH model if the author uses Langevin damp factor = 1ps
Mpipi Model, the author uses Langevin damp factor = 50ps
SOP IDP model, the author uses damp factor = 0.5 ps

Suppose anyone knows about the concept of the Langevin damp factor and how we can calculate for different systems. Please let me know.