Hyperfine Interactions of Excited Nuclei in Atomic Systems

The idea of utilizing an excited nucleus as a probe to observe the hyperfine interaction in free atoms was evident from the very birth of the perturbed angular correlation method [2.1]. Since that time, there have been many developments in experimental methods and in our understanding of the different atomic systems in which measurements can be performed, and many interesting results have been obtained. There have been periodic reviews of the status of the field, the most recent of which was made by GOLDRING [2.2]. Together with his students and former students, Professor Goldring has made many of the important advances in this field of physics, and his review is an excellent source for more information on some of the topics covered in this chapter. Because of the existence of this excellent review by GOLDRING, which places strong emphasis on the time integral methods, I have tended in this chapter to emphasize more the techniques and methods for dealing with longer-lived nuclear levels where one can apply time differential methods.