[gmx-users] Regarding POPE " H " atom type modification

[Oliver Mirus]

Hi,

naga raju wrote:
> Dear gmx users,
>            I am trying to equilibrate POPE lipid
> bilayer. As per mailing list
> (http://www.gromacs.org/pipermail/gmx-users/2006-May/021416.html.),
> C6/C12 parameters are converted into sigma/epsilon. I
> modified " H " atom type to opls_369 in pope.itp
> file(show below).
> [...]
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>  My question is 
>                1) Where I have to modify H atom type
> given in pope.itp file ( given that "added atomtype H
> from opls_369 to match H expected by pope.itp" in
> atomtypes section:
> http://www.gromacs.org/pipermail/gmx-users/2006-May/021416.html.)

in this case modification of pope.itp is not necessary. You have to make 
this change in "ffoplsaanb.itp":

Copy the line

opls_369   H   1    1.00800     0.400       A    0.00000e+00  0.00000e+00

to the bottom of the "[ atomtypes ]" section and replace "opls_369" by "H".

And don't forget to follow this additional tutorial by Chris Neale:
http://www.gromacs.org/pipermail/gmx-users/2006-September/023761.html

regards

Oliver