Integrating dissipative particle dynamics with energy conservation

To suppress secular energy drift in dissipative particle dynamics simulations with energy conservation, we introduce an additional pairwise particle dynamics that allows for a microscopic energy fluctuation while conserving the total linear momentum of the system exactly. The pairwise dynamics may be regarded as an adaptation of the thermostat in isothermal dissipative particle dynamics, but leads to microcanonical instead of canonical ensemble at equilibrium and allows for a nonuniform temperature field at a steady state. The method is also effective in suppressing secular energy drift when used in combination with reverse nonequilibrium molecular dynamics moves. All of the equilibrium and transport properties we computed were unaffected by this additional pairwise dynamics.