﻿Atomic Model with a Magnetic Core. 719 



taken as -JEA 2 0, where E is the total positive charge, which 

 we shall assume equal to ~Ne» We have no direct evidence 

 as to the value of A 2 X2, but if, for convenience, we assume 

 that it has the same value as a 2 co for an electron in the ring, 

 the magnetic moment of the rotating core becomes -I-Nea 2 ft). 

 But a magnetic moment of -|<?a 2 a> is equivalent to 5 magnetons. 

 Consequently the magnetic moment of the core is equivalent 

 to 2$ magnetons. The resultant magnetic moment for the 

 atomic model would be the difference between the 2N 

 magnetons of the core and the 5n magnetons of the ring. 

 Thus the magneton may be introduced as a unit for measuring 

 magnetic moments without necessitating the existence of a 

 single magneton as an independent entity. 



It is not intended that this model should do more than 

 serve as a crude illustration of the structure of an atom, for 

 there can now be little doubt as to the complex character of the 

 core at least in the case of the heavier elements. In par- 

 ticular a spherical or spheroidal distribution is not an essential 

 feature of the proposed atomic model. It may be that all 

 parts of the core must move in one plane. There are 

 obvious outstanding difficulties such as the way in which 

 the parts of the core hold together so as to form a stable 

 system. Passing over these difficulties, the resultant mag- 

 netic moment of the atom with a spherical core would be 

 either the sum or the difference of 2N and 5n magnetons, 

 according to the relative directions of rotation of the core 

 and the ring. 



It would seem that the diamagnetic properties of such an 

 atom would depend mainly on the ring, if a is much larger 

 than A. For the expression for the magnetic susceptibility 

 would consist of a series of terms of which the most important 



would be k = 



Aim 

 Pascal * has shown that the molecular susceptibility of a 



large number of chemical compounds can be calculated by 



where V is the total volume, 7c the radius of gyration for a uniform 

 distribution of mass, and E the total charge of the rotating system. 

 ) Thus both for a sphere and for a spheroid rotating about an axis of 

 symmetry, the magnetic moment is £EA J i2. 



We may note here that if the electrical distribution is associated with 

 a proportional distribution of mass, the total mass being SDR. the angular 

 momentum is 2ft/»r£2. If we assume that this is a multiple of Jt. 



say tA/27t, the magnetic moment may be written sr. x , -. 



* Pascal, C. R. vol. clii. pp. 802-865, 1010-1012 (191 L), 



