GROMACS version:

GROMACS modification: No

Please help me to calculate cohesive energy density in gromacs simulation md calculation

This paper goes over procedure to calculate CED. In a nutshell, you can use following formula to get CED.

CED = \frac{-E_{inter} \rho}{N_m M_w}

E_{inter} = Intermolecular energy

\rho= density

N_m= Number of molecules

M_w= Molecular weight

Calculating E_{inter} is tricky, you need to decide based on your system.

Regards,

Masrul