Hi, I am trying to perform a NVE simulation of water at 300K using the TIP4P potential, with 309 molecules.
I do 50ps of equilibration with a Nose-Hoover thermostat with tau_t = 1 first to get the water at 300K. However, when I then do my main run, the temperature suddenly jumps up at the beginning of the run to as high as 3000K ! The temperature then remains around 3000K with the normal slight upward drift. relevant parameters: dt = 0.001 ; time step integrator = md nstlist = 1 ; update pairlist ns_type = grid ; pairlist method coulombtype = PME vdwtype = shift pbc = xyz rlist = 1.03 ; cut-off for ns rvdw = .93 ; cut-off for vdw rcoulomb = 1.03 ; cut-off for coulomb Tcoupl = No ; temperature coupling I'm not sure what causes this. I've tried a number of things, including skipping the equilibration and just using initial velocities at 300K, but that leads to a similar problem. I also tried both the md-vv and md integrators, with the same result. This problem does not occur in version 3.3.3, so that's the version I've been using. However, it does occur in 4.5.5 and also 4.1.1 (if I remember correctly). I'd like to switch to version 4.5.5 to take advantage of the velocity-Verlet integrator and multithreading capabilities. -- View this message in context: http://gromacs.5086.n6.nabble.com/Sudden-rise-in-temperature-in-NVE-simulation-tp4999347.html Sent from the GROMACS Users Forum mailing list archive at Nabble.com. -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Only plain text messages are allowed! * 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