[gmx-users] QM/MM energies

[Jon Mujika]

Dear gmx users,

I am performing some QM/MM optimizations using the ORCA interface in
order to compare the energies of different structures of the same
system. However, I have some questions related with the energy terms.

In the output file the "potential" and "Quantum Ener." terms are
printed out. The question is: does the Potential term include the QM
energy? That is, is the "potential" energy the total QM/MM energy, or
only the MM part of the total energy? On the other hand, since I am
using the electronic embedding approach (QMMMscheme=normal in the .mdp
file), I assume that the QM/MM electrostatic energy is included in the
QM term. Is that correct? And what about the QM/MM van der Waals
energy?

I ask so because I try to calculate the potential energy from the
different terms provided in the output, but I can't reproduce the
potential energy.

Thanks for you help

Jon