It has been stated, [3], that the idea of a physically rotating electron possessing finite extensions can only be considered from a heuristic point of view. The reasons being that calculations of surface velocity would exceed the speed of light, if values of angular momentum and magnetic moment are to agree with those determined experimentally. However, it was shown in [4] that it is entirely possible for the spin circumference of a rotating body, to be accelerated to the speed of light while the mass remains finite. In fact it was postulated that as a result of this and the primary condition of existence in D₀, (see [7]), that in a corpuscular theory of atomic structure, it may very well be this mechanism that initiates an orbital transition and thus a spectral emission. This proposal will be addressed further in this paper. Hence the possibility that the surface of a spinning electron could exhibit a spin circumference velocity of the speed of light, (or more correctly, the terminal velocity of D₀), should not be the cause to reject the idea of a physically spinning electron in any theory of atomic structure. However, there are still problems with this approach. First, it means that subsequent to the formation of an atom, in which electron spin exists in one direction, there is no apparent mechanism for effecting spin reversals, as is evident in some electron orbital transitions. Also, it is evident that many orbitals can contain electrons with either direction of spin while others can contain electrons with only one direction. This is not a randomised feature and clearly infers that the orbital configurations extant within the atom, must contain a means by which this feature is controlled. Accordingly, it is considered likely that the origin of electron spin is also contained within the structure and embodies the mechanics which provide it with the above attributes. To address these apparent difficulties, a speculative mechanism for electron spin is presented as follows.

In [1], and the literature in general, it has been shown that the relativistic increase in mass of the orbiting electron, is instrumental in contributing to its fine structure emission/absorption spectra. It does not therefore seem unreasonable to consider other relativistic effects, as the possible cause of electron spin. Accordingly, it is suggested that due to the orbital velocity being a significant fraction of the velocity of light, as well as a relativistic increase in mass, the electron also experiences a Lorentz-Fitzgerald contraction in the direction of motion. Now consider Fig. 2.1 below.

Due to the Lorentz-Fitzgerald contraction in an elliptic orbit, the electron surface area subtended to the nucleus will be configured asymmetrically about the centre line joining them. e.g., in Fig. 2.1, the surface area a_up as opposed to the surface area a_low. Accordingly, the coulomb force of attraction between the two particles will also be asymmetrically distributed about the centre line. This will cause the electron to spin, in Fig. 2.1, in the direction shown. It would appear that the greater the orbital velocity, the greater will be the degree of contraction and hence the potential spin rate. However, the spin rate will be entirely governed by the quantisation requirements for the spin motion to be stable. In this respect it is noted that the mechanism causing spin takes place in a perfect vacuum. Therefore the torque imposed on the electron due to coulomb charge asymmetry experiences no resistance apart from inertia.

When the above process is applied around a complete elliptic orbit, the nature of the spin changes as shown in Fig. 2.2 below.

As the electron orbits the nucleus, due to the eccentricity of the orbit, the surface area of the electron subtended at the nucleus changes orientation. The change is such that in quadrants 1 and 3 a clockwise, (spin-up), motion is induced while in quadrants 2 and 4 aa anti-clockwise, (spin-down), motion is induced. The shaded areas in Fig. 2.1 indicate possible dead zones where the asymmetry of distributed surface charge on the electron about the centre line is insufficient to induce spin. These dead regions would occur because at these points, the orbit path is almost/exactly normal to the radius vector to the nucleus, and the subtended angle of the electron surface is symmetrical about it. Thus it is obvious that in circular orbits, in which the radius vector from the nucleus to the orbiting electron was normal to the orbit path at all times, there would be no electron spin induction. However, when electron transitions from elliptic orbits to circular orbit paths occur, as a result of the conservation law of angular momentum, the electron would arrive in the circular orbit still possessing spin. The precise mechanism governing orbital transitions in circular, (and elliptic), orbits depends upon other factors in addition to electron spin, and will be discussed later in this and finalised in a future paper.

It is thus concluded that in all atomic orbits the electron will possess spin, in circular orbits, either spin-up or spin-down, and in most elliptic orbits in which spin induction occurs, both states.

One consequence of this proposed mechanism for electron spin induction, is that the driving force is identified as the asymmetry of the coulomb attraction between the nucleus and the orbiting electron. It is therefore necessary to determine what effect, if any, this would have upon the orbital principle quantum number.

Dn_(or,sp) is a possible orbital principle quantum number variation due to the effects of electron spin. v_sp is the velocity of the mass effective radius of the electron in axes of D₀ due to spin.

Assume for simplicity, but with no loss of generality, that the orbit is "near" circular so that in (2.1) the orbit path elemental may be approximated by

G_gyr is the radius of gyration of the electron.

y is the electron spin angle f is the electron orbit angle M_sp is the non-relativistic spin angular momentum.

Therefore, even though the electron spin mechanism proposed here is effectively driven by the nucleus/electron coulomb interaction asymmetry, it does not affect the quantised orbital energy.

Two final points, first, with spin reversals taking place within all the elliptic orbitals, there would also be reversals of spin angular momentum and spin quantum number, (see next Section). This would then, in most cases, (governed by the Selection Rules, see Section 4), permit transitions from these orbitals with either spin direction. Secondly, it is important to note that the effect described here would also cause the nucleus to spin.

2.3   Relativistic Mass Correction Due to Spin.