SOME CONTEMPORARY ADVANCES IN PHYSICS- llll AM) 



sl.itfs of the ionizi-d-lu'liuin atom (ami |)ri'siimal)ly those of tlic 

 liy(ln)Ki'n atom) are not so radically ditTi-riMU from lliosi- of the scMliuiu 

 atom as thoy sicmoti to be; some of the apparent dilTererues heiiin 

 traceable to the fact that corresponding levels in the/, the </, the /> 



2 



A = a 



Hg. 8 — Diagram of the stationary states of ionized helium, resolved to account for 

 the fine structure of the spectrum lines 



