[gmx-users] Regarding energy calculation of head groups

[Raju Lunkad]

Dear all Gromacs users,
I wanted to calculate the enthalpy of headgroups of the surfactants. In
"mdp file" I have mentioned the energy as N4_O2 (Surfactants head groups)
but I am getting the following error:

 atoms 1 and 4 in charge group 1 of molecule type 'BTM' are in different
energy groups

I am not sure but in my opinion,  the error is coming because of the N4
contains  -0.5 charge and O2 contains -0.7 charge.
Kindly tell me how to mention energy groups in "mdp file" with charged
atoms.

Best regards,
Raju Lunkad