There is a problem when we try to use the collinear Hamiltonian. The error is that it cannot find an appropriate model.
This means that we need to decide on the appropriate model (probably TBexp.py).
I'm also a little confused about why we are adding in noncollinear des terms (what is des?) to the collinear Fock matrix in pylato/hamiltonian.py. I think @mb4512 wrote this originally, do you recall, Max?