Spin-1 Electrodynamics with an Electric Quadrupole Moment

The quantum theory of the electromagnetic interactions of a charged spin-1 particle is investigated, within the framework of canonical field theory. An earlier treatment of this problem by Lee and Yang is generalized so as to include an arbitrary quadrupole moment. Some difficulties connected with the lack of relativistic covariance of the theory can be overcome, without using Lee and Yang's "$\ensuremath{\xi}$-limiting formalism," provided one allows for direct scattering among the charged particles.