Hi, I am interested in doing a membrane-type simulation, in which I have all-atom membrane "walls" parallel to xy plane, at z = -z_0 and z = +z_0 (where z_0 is a constant). I would like to run an NPT simulation at 1 atm.
What type of pressure coupling should I use? Isotropic pressure coupling requires only one input value (either compressibility or reference pressure ref_p), whereas I think that semiisotropic, anisotropic, and surface-tension pressure coupling require specification of both the compressibility and ref_p (tensors). Clearly, I should not use isotropic pressure coupling, because clearly my system is not isotropic. However, what if I do not know and cannot find in the literature the compressibility of the liquid system that I am placing between the membrane "walls"? If I do not know the compressibility very accurately or at all, then it seems that I cannot use semiisotropic, anisotropic, or surface-tension pressure coupling. If you have time, I would like to ask an additional question. Now suppose I know the compressibility of the liquid between the membrane. Now what pressure coupling type should I use; should I use semiisotropic, anisotropic, or surface-tension pressure coupling? Both semiisotropic and surface-tension look reasonable. In the manual (http://manual.gromacs.org/current/online/mdp_opt.html#pc), semiisotropic pressure coupling is useful for systems that are isotropic in x and y, but different in z (which is the situation I have here). Surface-tension also looks like it describes a similar situation, but it requires the specification of the surface tension of the liquid, which I do not know. I am sorry that my questions are quite vague. If you have time, do you have any general thoughts? Or can you please recommend any papers that would help me understand and choose between the pressure coupling types? Thank you very much for your time! Andrew DeYoung Carnegie Mellon University -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
