where d αβ = ⟨ψ α |d ˆ|ψ β ⟩ results from dotting the coupling vector into the transition dipole moment between adiabatic states α and β or the total dipole moment of state α when α = β; this quantity also depends explicitly on the nuclear coordinates, but we are suppressing the dependence on R in our notation for simplicity. The transition dipole moments are purely electronic, while the total dipole moments have both an electronic and nuclear contribution. Finally, the dipole self energy has the form