[ESPResSo-users] parameters about conservative force in DPD method

[guozhicheng222]

Dear all

       I don not understand the number of parameters in the DPD interaction used in ESPresSo simulation. The command form described as follow:

inter type1 type2 inter_dpd gamma r_cut [WF wf tgamma tr_cut TWF twf]

Obviously, there is just one parameter of gamma to depict the dissipative force and random effect derived from the fluctuation-dissipation relation (σ²=2γk_BT, σ and γ denote the strength of noise and friction, respectively). However, the force acting on a particle has three parts, each of which is a sum of pair forces. The three contributions are a conservative force F_ij^C, a dissipative force F_ij^D and a random force F_ij^R. Therefore, I want know how to describe the conservative term (F_ij^C) in ESPresSo simulation. Moreover, what is the way of analyzing the chemical bond broken in ESPresSo based on DPD method. I am sincerely waiting for your response. Thanks!

 

Best wishes!

 

Zhicheng Guo