320 



BELL SYSTEM TECHNICAL JOURNAL 



Table of Nuclear Magnetic Moments 



The values are expressed in terms of the unit (eh/4-n-mpC) customary in such tables 

 (though for no very good reason) and sometimes called the "nuclear magneton." 

 They are collected from the same sources as those in the Table of Nuclear Spins, and 

 reduced to at rnost two significant figures; in cases of discrepancy, Schiller's value is 

 the one usually taken. Those marked S are the ones obtained by Stern and his 

 school; those marked R are obtained by Rabi and his school; those marked H or not 

 at all are deduced from optical observations on hyperfine structure. I have heard 

 the uncertainty of these last put at twenty per cent by one expert in the field, but 

 some authorities would set it even higher. For the isotopes of hydrogen, the sign is 

 unknown. 



The ratio of the magnetic moments of two isotopes of a single element may some- 

 times be calculated from hj/perfine-structure with less uncertainty of theory than the 

 value of either moment separately. For such ratios the following values are available: 



Cu63/Cu" = 1.00; 

 SniiVSniis = 1; 



Ga«VGa'i = 1.27; 

 Sb'2VSb'23 = 1.36; 



Rb"/Rb" = 2.04; 

 Hgi99yHg2oi = - 1.11; 



Cdii'/Cd'" = 1; 



'I-1203/X1206 = 1.02. 



The experiments of Rabi's school and those of Stern's indicate a value of about four 

 for the ratio of the moments of proton and deuteron; this is substantiated by L. and 

 A. Farkas (Nature, 135, 372; 9 March, 1935) who measure the rates of the reactions 

 whereby ortho-hydrogen and ortho-deuterium transform themselves into the para- 

 forms (and reversely) in the presence of oxygen; from measurements made at three 

 different temperatures they get for the ratio the three values 3.85, 4.03, 4.07, which 

 agree (they say) "within the limits of the experimental error, which is less than 

 five per cent." 



