[ESPResSo-users] DPD with explicit solvent

[Narges Nikoofard]

Dear all,

I am trying to simulate the self-assembly of some specific amphiphilic polymers, with explicit coarse-grained beads for water. In case that both statics and dynamics of the system are of interest, is it correct to use DPD method with explicit water beads?

I add DPD to the code using this command:
thermostat dpd 1.0 $gamma $r_cut

We start from a random configuration for the polymers and the command "galilei_transform" is used before starting the integrations.

I have also some questions about using the command:

(1) I am not sure the suitable value for gamma. For some gamma values, the system blows up.

(2) What value should be used for the step size, after choosing a value for gamma? Is it still correct to take gamma/time_step~100 (similar to langevin)?

(3) What is the suitable value for r_cut when differently sized beads are present in the simulation? Is it correct to use r_cut=[expr 1.12246*sig_max], where sig_max is the maximum value used for the Lennard-Jones sigma in the simulation?

(4) How much dpd is more time-consuming relative to langevin thermostat?

I would be grateful if someone could kindly help me in this respect.

Many thanks,

Narges Nikoofard