[gmx-users] free energy perturbation

[Giovanni Bussi]

Dear all,

I am using GROMACS with free-energy perturbation to switch off a
molecule gradually. If I understand correctly, the parameter
"couple-moltype" is used to select which molecule to switch off. Is it
possible to switch off *two* molecules at the same time? (e.g. a
charged molecule and a neutralizing ion).

In case not, is there any problem related to the fact that in one of
the topologies the total charge is not zero?

Thanks a lot,

Giovanni