[ESPResSo-users] Choice of timestep and langevin-gamma

[Clemens Jochum]

Dear all,

I read previously that for a system with Temp = 1. and mass = 1. a good
value for the timestep is 0.01. I have Temp  = 2.5 and mass1 = 20 and
mass2 = 660. Is it correct to assume that I can scale the timestep
inversely to the thermal velocity with a factor of (m / kT)^(1/2) ~ 3
(using the mass1)? I have been using a timestep of 0.05 = 5e-15 s so far
without any major problems.

The other parameter I am concerned about is gamma of the
langevin-thermostat. So far I just used gamma = 1. = 10 ps^-1, which as
I recently read is a little bit high. In my system I simulate a charged
macromolecule with counter-ions in an implicit solvent (water). Is a
value of gamma = 0.2 = 2 ps^-1 a good fit?

Best,
Clemens