Anwser Q1

The hamiltonian is given by H = T + U. The U term stands for potential energy, I think the potential energy will be given by coulomb interactions in this case (for all combinations of particles, so nuclei + nuclei, electron + electron, nuclei + electron). The T term stands for kinetic energy, in this case the kinetic energy of the particles in question (nuclei and electrons), given by something like p^2/(2m).