[gmx-users] Doubt in specifying combination rule

[Apramita Chand]

Dear GROMACS users,
 I want to use the geometric mean of both sigma (sigma i sigmaj)and
epsilon(epsilon i epsilon j) as a combination rule in my simulation.
According to the combination rules in the manual, the combination 3
incorporates Vii=sigma and Wii= epsilon along with geometric mean of Ci(6)
Cj(6) and Ci(12)Cj(12) terms.
So can I use combination 3 in the [defaults] section of the forcefield.itp ?
If not, how do I achieve this particular combination?

Thanking you,
Yours sincerely,
Apramita