5" 



Tables 619-621 

 TABLE 619. — Resonance Lines 



(LaPorte, Meggers, Journ. Opt. Soc. Amer., n, 462, 1925.) 

 An electron jump which involves the lowest term and gives rise to the line of greatest 

 wave length, i. e., the firsttransition which is connected with emission and requires the 

 least energy for excitation, in spectra where there is no metastable level lying close to the 

 lowest term gives a resonance line. 



TABLE 620. — Electron Impacts in Gases 



(Langmuir, Jones, Rev. Mod. Phys., 2, 233, 1930.) 

 Probabilities that an electron, while going through gas at 1 mm pressure, 20°C, will collide 

 inelastically, Pk, elastically, P e , so as to produce 1st excited state, P r , or so as to ionize Pf 



TABLE 621. — Average Life for Various Quantum States of Excited Atoms 



Theoretical values of ionized helium (Maxwell, Sugiura, Stack.) 



The values for H are 16 X those for He (Sugiura, 1927, 1929). It is to be noted that the 



average life is longer for progressively higher quantum states. 

 _ Maxwell 1931 obtains 1.1 ±0.2 X IO" 8 sec. for av. life 6th quantum state (cf. 1. 18 X IO" 8 ) 



given above. Maxwell's qualitative observation on first four lines of 4686 He + series, 



4>3> 5>3< 6>3, 7>3, show definitely the longer life for higher quantum states. 



Poole (Phys. Rev., 33, 22, 1929) metastable Hg atom (Z 3 P ), max. time 4.2 X io 4 sec. 



(6.8 mm). 



See Ann. Phys., 83, 294, 1927, for early summary, including following: 

 O spark, 467, 459mm, 1-53 X io- 8 sec. Ca spark 3933A, 3968A, 0.65 X io- 8 sec. 

 O arc, 6158, 4368A, 14.9 " Ca arc 4226A, 3.4 " 



Koenig, Ellett. (Phys. Rev., 39, 576, 1932) give for 2 3 Pi state Cd, 2.5 X io- 8 sec. 



Smithsonian Tables 



