Subsequent to the initial resurrection of the Bohr/Sommerfeld theory of atomic structure in [1], in which the electron is treated as a real physical particle, this paper continues the development of that theory by incorporating the mechanical effects of electron spin.

Electron spin is a completely separate motion from that of the orbital, having a separate rotational path, a circumferential one. For these reasons, electron spin must have associated with it, a separate matter wave from that of the main orbital rotation. This spin matter wave, in order for the spin motion to be stable must be independently quantised. The spin quantisation process, being unique will consequently result in a spin principle quantum number. The derivation of this is the subject of Section 3.0. The manner in which this then contributes to the emission spectra, is covered in Section 4.0 via discussion of the photon emission mechanism, and the development of the electron transition Selection Rules. Prior to these derivations however, it is necessary to address some preliminary factors to characterise the spin motion. The main one of these is the nature and origin of electron spin. This and other salient points are discussed in the next section.