MAXWELL FIELD OPERATORS, THE ENERGY DENSITY, AND THE POYNTING VECTOR CALCULATED USING THE MINIMAL-COUPLING FRAMEWORK OF MOLECULAR QUANTUM ELECTRODYNAMICS IN THE HEISENBERG PICTURE

The time-dependent total electric-and magnetic-field operators in the neighborhood of a molecule are calculated in the minimal-coupling form alism of Coulomb gauge quantum electrodynamics. The spatial variations of the vector potential are taken into account, enabling the fields c orrect to second order in the electronic charge to include magnetic-di pole-and electric-quadrupole-dependent terms in addition to contributi ons arising from the electric-dipole interaction term. The minimal-cou pling Maxwell fields are compared and contrasted with their analogs pr eviously derived in the multipolar framework. The electric-and magneti c-radiation-field operators derived in the minimal-coupling formalism are then used to calculate the expectation values of the Thomson energ y density and the Poynting vector, and the results obtained are shown to be identical to those of the multipolar theory.