404 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



pages is now called the spectroscopic splitting factor; the other has been 

 set apart as the ''gyromagnetic" g, and some people have even taken 

 to writing it as g' , which seems rather unfair to the senior g. It seems to 

 be a general rule that when one of the two is greater than 2.00 the other 

 is smaller than 2.00; and in the case of the Heusler alloy, they may well 

 coincide. 



ACKNOWLEDGEMENT 



Among the many who have helped me with this article I wish to 

 extend especial thanks to Charles Kittel, A. F. Kip, W. D. Knight, 

 M. E. Packard, E. M. Purcell, J. H. Van Vleck and W. A. Yager; and 

 to Messrs. Packard, Purcell and B. Bleaney for prints of the illustrations 

 captioned with their names. 



REFERENCES 



This makes no pretense of being a bibHography of magnetic resonance : such an 

 enterprise would cover more pages of this Journal than these articles themselves. 

 It is somewhat, but not much, more than a listing of the sources of the data quoted 

 in the articles, with the names which have been omitted in the belief that names 

 tend to slow down exposition. Many relevant papers, with an abundance of foot- 

 note references to anterior work, are to be found in what I abbreviate by P.I. C.S.R. 

 ("Proceedings of the International Conference on Spectroscopy at Radiofrequen- 

 cies, Amsterdam, 1950" separately published and also printed as part of Volume 

 17 of Physica). 



The locus classicus for the nuclear resonance absorption is the paper of Bloem- 

 bergen, Purcell and Pound {Phys. Rev. 73, p. 670, 1948); the first publication of 

 this school is by Purcell, Torrey and Pound in Phys. Rev. 69, p. 37, 1946. The 

 locus classicus for the precession-theory and the nuclear-induction method is the 

 paper of Bloch (Phys. Rev. 70, p. 460, 1946), followed by the first lengthy descrip- 

 tion of nuclear -induction measurements by Bloch, Hansen and Packard (ibid. 

 p. 464); the first publication of this school is in Phys. Rev. 69, p. 127, 1946. The 

 discovery of nuclear magnetic resonance by the molecular-beam technique was 

 disclosed by Rabi, Zacharias, Millman and Kusch in Phys. Rev. 63, p. 318, 1938, 

 and a more detailed account is given ibid. 55, p. 526, 1939; consult also the paper 

 of Kellogg, Ramsey, Rabi and Zacharias z6 id. 57, p. 677 (1940) for the resonances 

 of protons and deuterons in molecular beams of H2 , D2 and HD. 



The reference to the article of G. E. Pake {Am. Jour. Phys. 18, pp. 438-452 and 

 pp. 473-486, 1950) is here repeated to draw attention to this excellent survey of 

 nuclear magnetic resonance and relaxation. Another survey article is that of 

 Rollin, Reports on Recent Progress in Physics, 1948-49. The reference for the 

 chemical shift in ethyl alcohol (Fig. 7 of Part I) is Arnold, Dharmatti and Packard, 

 J. Chem. Phys. 19, p. 507, 1951 . For the influence of F-centres on nuclear relaxation- 

 time see Hatton and Rollin, Proc^ Roy. Soc. 199, p. 231, 1949. 



For the final experiments on determination of g for electrons in hydrogen atoms 

 see Koenig, Prodell and Kusch {Phys. Rev. 88, p. 191, 1952); references to earlier 



