We derive multipolar gravitational radiation in the framework of quantum field theory in which the atomic states are treated nonrelativistically, and the gravitational waves are quantized. By relaxing the constraint eik·x ≈ 1, the multipolar transition rate is calculated when one graviton is emitted. As a consistency check, we recover the semiclassical result in the dipole approximation regime. Besides, we show that the dynamical mechanism that gives rise to spontaneous graviton emission by an atom, has a profound consequence on the lifetime of the atomic electron.
