[gmx-users] position restraint on some solvent molecules
v.gogonea at csuohio.edu
Mon Jun 2 16:40:01 CEST 2003
Dear GROMACS users,
Is it possible to impose position restraints on only a selected subset
of solvent molecules. If yes, how can this be indicated in the topology
file? If this is not possible, can anybody point to me to the function
in the GROMACS code which sets up the position restraints for solvent?
The second question concerns simulation with frozen groups. I was
struggling for the past couple of weeks to perform a simulation in
which part of a protein and solvent is frozen (using the spc model for
water). It happens that after a while a moving water molecule collides
with (getting very close to) a frozen water molecule and the simulation
crashes giving NaN for coordinates of one water molecule and NaN for
energy. I was thinking to impose position restraints for frozen water
molecules which are accessible to moving water molecules, but I didn't
figure out how this can be done.
Any help will be greatly appreciated.
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