Question on QM/MM and CDFT in CP2K

[Moon Yang]

Dear CP2K community,

I am trying to run QM/MM simulations using CP2K coupled with GROMACS to investigate charge transfer within a protein solvated in water.
My goal is to compare the structures and energies between two states, before and after charge transfer between two residues in the QM region, for which I am attempting to employ constrained DFT (CDFT) to control the charge localization.

Although I’m not yet familiar with all the details, the energy minimization runs seemed fine without CDFT.
But I have been struggling to introduce CDFT into the calculation, and after several attempts, now have encountered convergence issues during test runs.

I am attaching my input files for both cases (with and without CDFT).

Any insights, suggestions, or example inputs related to CDFT or charge constraints in CP2K would be greatly appreciated.

Thank you very much for your time and advice.

Best regards,
Moon