from the Quantum Theory of Spectral Emission. 625 



If we suppose that the spectrum is due to ionized atoms in 

 which the field can be approximately represented as a central 

 charge of E=/>e and a doublet of different strength L'. 



We have, by a similar reasoning, energy in a statical path 



_ 2tt_ 2 g*E*m 



A 2 f «' / ' 'W W 2 



_ -p 2 W i 



( *' ■ {1 'W \\ v 



where N = Rydberg number. 



As a result of numerous investigations on the nature of 

 the spectral series, it has been shown that for many elements 

 the different series can be grouped according to the following- 

 scheme : — 



f P- Series : 



v = (1-5, s) — (m, pi) -\ m = 2, 3, 4 ... . 



-KP2) j 

 II. Subordinate Series : 



" = ? 9 ' Pi) rrit'1 -=2,3,4.... 



1st Subordinate Series : 



Companion : 



v = (2, Pl )-tm,d') m = 3,4, 5, 



v = (2, P2 )-(m,d"). 



N 

 Symbol (m,f) stands for — '- ,- 2 according to Rydberg, 



N . 



and r-rg according to Ritz. 



{ ,n+ - r+ ij 



The frequency of the lines emitted thus appears as the 

 difference of two terms, each of which is to be regarded as 

 corresponding to the energy in a definite statical path, on 

 the Quantum theory. Sommerfeld * has recently given 

 reasons for assuming that in any series of statical orbits 

 corresponding to the different kinds of 5, p, and d terms 

 the azimuthal quanta generally preserve a certain definite 



* Sommerfeld, Verh. d. Phys. Ges. May 1919. 



