Photons symmetric electromagnetic fields

Electron spin may interact directly 22,67,123 with the oscillating electromagnetic field of a photon. In this case the transition operator,, /(t) of Section IV, does not commute with the symmetric group S f, so that direct transitions between pure singlet and pure triplet states are allowed. Selection rules for this type of transition may be derived, as has been done by Chiu,22 by noting that f(t) has components which transform as different representations of the double group SF 0 (see Sect. VIII). 

The electromagnetic field of the composite photon contains advanced and retarded components, without any causality breach. The forcefield of doublet is described by the symmetric Maxwell s equations [87b]. Three different regions appear in the forcefield inner, near-field, and far-field. Longitudinal components of force are always present. However, in the far field, they dissapear for practical purposes. In this sense, the equations developed contain the standard set as a limiting case. 

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