I am interested in using PSI4 to develop a DFTB parametrization protocol. These parameters are obtained by performing DFT calculations on free atoms with a Hamiltonian that includes a confinement potential of the form v = (r/ro)^m .

I’d like to know if there is an easy way to include additional terms to the electronic Hamiltonian using PSI4 or PSI4Numpy functionalities, and if not, where in the code I could adapt a pre-existing routine to create a new function for this task.

All collected potentials will be added to the Fock matrix at the C++ level. The input matrix is a psi4.Matrix class (can be build from a numpy arrray Matrix)