Is your feature request related to a problem? Please describe.
I am trying to write a QM/MM interface of xtb and charmm MD package, but I cannot find a proper way to calculated the force on MM point charge.

Describe the solution you'd like
If the force on MM point charge is given directly is better.
Another way is to give the electric field on each point charge site, so the force can be calculated easily.
Hope this can be in the C API.

Describe alternatives you've considered
Using the cube file to calculate the force on each point can also work, I just want to know if there is a better way to go.