﻿Radioactive 1 vans formations. 



983 



The values of* X and d were taken from the paper by 

 Geiger and Nuttall (loc. cit.). 



0-6 



0-5 



2 



0-4 



0-3 

























Op 





















$& 





















pct^ 





s 















^ 











to* 



V 



(\o- 







































+ 4 +£ 



-4- -6 -8 -10-12 

 &y A- ^lo<j cZ 



14- -16 



The equation (1) therefore represents approximately the 

 relation between § and \; so that the assumption that the 

 energy necessary for an a particle to escape is the same in 

 all cases appears to be approximately true. 



The two lines are parallel, so that for both series of pro- 

 ducts b is the same, and the slope of the lines gives 6 = 205. 



Hence U = _. 



For helium m/R = -i/2 X 4'2 X 10 7 and j3= 7'5 x 10~ 28 ; so that 

 Q=l-6 x 10 13 calories per gram molecule. The work for a 

 gram molecule of electrons to escape from platinum is about 

 10 5 calories; so that the work for an a particle is about 10 8 

 times greater. The work for an electron to escape from 

 platinum is about that necessary to separate two ionic 

 charges (e) from a distance of l0~ 8 cm. or the radius of 

 molecular action. The work for an a particle to escape is 

 therefore about that required to separate two charges 2e from 

 a distance of 10 ~ 16 cm. 



^ We may say therefore that in the escape of electrons at 

 high temperatures and in ordinary chemical actions electrons 

 are separated from distances of the order of the radius of 

 molecules, while in radioactive changes electrons are separated 

 from distances about 10- times smaller. 



