[gmx-users] About coulmb & Vanderrwalls cutoff
jalemkul at vt.edu
Wed Jun 5 04:03:57 CEST 2013
On 6/4/13 9:48 PM, vidhya sankar wrote:
> Dear Justin Thank you for your Previous reply.
> As yo mailed me The Defaut Value for vandewalls and Electrostatics in GROMOS96 53A6 is PME option
> s_type = grid
> nstlist = 5
> rlist = 0.9
> rcoulomb = 0.9
> rvdw = 1.4
> But in you Umbrella sampling you are using GROMOS96 53A6 FF there you quoted different Parameters in your em.mdp file
> nstlist = 1 ; Frequency to update the neighbor list and long range forces
> ns_type = grid ; Method to determine neighbor list (simple, grid)
> rlist = 1.4 ; Cut-off for making neighbor list (short range forces)
> coulombtype = PME ; Treatment of long range electrostatic interactions
> rcoulomb = 1.4 ; Short-range electrostatic cut-off
> rvdw = 1.4 ; Short-range Van der Waals cut-off
> pbc = xyz
> can i Take 1.4 instead of 0.9 value
The value of rcoulomb is a bit more flexible when using PME, but unless you have
a basis for changing it (and having demonstrated that the change is harmless),
you shouldn't deviate from the parameters given for the force field.
> oterwise is there is Any spcification according to system and BOx size
The contents of the system and size of the box do not dictate the parameters
that are set; the force field does.
Justin A. Lemkul, Ph.D.
Department of Biochemistry
jalemkul[at]vt.edu | (540) 231-9080
More information about the gromacs.org_gmx-users