[gmx-users] truncated LJ potential

[Makoto Yoneya]

Dear GROMACS experts:

I'd like to use a modified Lennard-Jones potential (smoothly truncated at
only the repulsive part) in the following.

V(r)
  = 4*epsilon*{ (sigma/r)^(12) - (sigma/r)^6 - (1/4) } for r <=
2^(1/6)*sigma
  = 0 for r > 2^(1/6)*sigma

Which routine should I change to realize this LJ potential modification
without any side effects.
I'd like to use this in some coarse-grained simulations.
Sorry if this is a FAQ.

Thank you for advance.

Makoto Yoneya, Dr.
AIST, Tsukuba
JAPAN
http://staff.aist.go.jp/makoto-yoneya/