I learned about dissipative particle dynamics (DPD) with Max, Upendra, and Ardeshir. It is an amazing tool for simulation of mesoscale systems including polymers and bio-membranes. The system size can be extened to µm ,and µs for time scale which is about 10^6 faster than regular molecular dynamics.
This post is for my learning process and materials of DPD.
Rob Groot seems to be the bigest name in the field of DPD. And he has really good slides for DPD. Here is the link.
In the presentation, he answered the question of how to parameterise DPD. The goal of it is to reproduce local thermodynamics which are measured by compressibility and solubility. Flory-Huggins theory are used for the solubility.
I tried to run dpd in lammps. With the input below.
# This is LAMMPS input script specifies a simple DPD simulation. # It reproduces Fig. 2 of Groot and Warren, J. Chem. Phys. 107, # 4423 (1997) units lj atom_style atomic comm_modify vel yes pair_style dpd 1.0 1.0 34387 # create simulation box lattice fcc 3 region mybox block -4 4 -4 4 -4 4 units lattice create_box 1 mybox create_atoms 1 box # define masses and interaction coefficient mass * 1 pair_coeff 1 1 25 4.5 # create initial velocities velocity all create 1.0 4928459 dist gaussian # change neighbor list parameters to avoid dangerous builds neighbor 2.0 bin neigh_modify delay 3 # specify simulation parameters timestep 0.04 thermo 10 # first equilibrate the initial condition fix 1 all nve run 500 dump traj all xtc 50 traj.xtc dump_modify traj unwrap yes dump traj_xyz all xyz 50 traj.xyz # production run run 50000
The gr plot I got from this simulation is the same as the plot 2 in the paper.