﻿-54 Y 



323 Y 



2-52 Y 



42% 



1-44 V 



454 Y 



•78 V 



-13 % 



--10Y 



3-89 Y 



2-00 Y 



35 % 



1-42 Y 



5-16 Y 



•56 Y 



6% 



•78 Y 



523 Y 



•88 Y 



42% 



432 The Disintegration of Elements by ol Particles. 



Table II. 

 Distribution of Momentum. 



H particle. Residual Nucleus. a Gain in 



me " Forward. .Backward. Forward. Backward, particle. Energy- 



Boron 202 Y - 1'75 Y 



Nitrogen 1*78 V -1'32 Y 



Fluorine 2-10 Y - T89 Y 



Sodium 202 Y -172 Y 



Aluminium... 234 V -211 Y 



Phosphorus... 210 Y -1-89 V VUT 5-13 Y 76 Y 15% 



The momenta are expressed in terms of the initial velocity 

 V of the a particle. The initial momentum of the a particle, 

 and consequently the sum of the momenta of the three bodies 

 after collision, is therefore 4V. Momenta in the direction of 

 the incident a particle are taken as positive, momenta in ths 

 opposite direction as negative. The percentage energy, 

 gained from the nucleus as a result of the disintegration, is 

 given in the last column, in terms of the initial energy of the 

 ol particle. 



It will be seen that in the case of nitrogen a considerable 

 part of the momentum of the a particle is communicated to 

 the main nucleus, a much greater part than in the cases of 

 the adjacent elements boron and fluorine. This indicates 

 that the H satellite of nitrogen is in relatively close 

 proximity to the main nucleus. It will also be noted that 

 while for the other elements there is a gain of energy from 

 the disruption varying from 6 per cent, for sodium to 42 per 

 cent, for boron and aluminium, for nitrogen there is a loss of 

 energy of 13 per cent. 



It is apparent from the above table that the distribution 

 of momentum among the three bodies varies considerably for 

 the different elements, but, in the absence of any definite 

 evidence of the validity of the theory on which the calcula- 

 tions are based, it seems inadvisable to discuss these differences 

 in any detail at the present stage. 



Cavendish Laboratory, 

 June 20, 1922. 



