[gmx-users] charmm in gromacs cut-offs

[tarak karmakar]

Dear All,

    It seems the problem in the cut-off schemes while using charmm force
field in gromacs persists even in the latest gromacs-4.6.1 version.
Recently I have posted regarding this problem came in gromacs-4.5.5
version. If anybody has already tested this issue in the latest version,
please leave a comment in the mailing list.

The cut-off parameters I have used are as follows

rlist                      = 1.2
rlistlong               = 1.4

; 7.3.10 Electrostatics
coulombtype              = PME
rcoulomb                    = 1.2

; 7.3.11 VdW
vdwtype                    = switch
rvdw                          = 1.2
rvdw-switch              = 1.0

NOTE 3 [file md_sim_ann.mdp]:
  The switch/shift interaction settings are just for compatibility; you
  will get better performance from applying potential modifiers to your
  interactions!

NOTE 4 [file md_sim_ann.mdp]:
  For energy conservation with switch/shift potentials, rlist should be 0.1
  to 0.3 nm larger than rvdw.

NOTE 5 [file md_sim_ann.mdp]:
  The sum of the two largest charge group radii (0.079732) is larger than
  rlist (1.200000) - rvdw (1.200000)

This part is reported as bug in gromacs -4.5.5 and required to be verified
by users through their feedback

http://redmine.gromacs.org/issues/1164

In this link it is showing affected version grom-4.6.1 !!

Thanks and regards,
Tarak