Elementary Nuclear Theory [antikvár]

PREFACE This book is not meant to be a textbook of the theory of atomic nuclei. It is merely a selection of certain topics in the theory, and even these topics are treated in only an elementary way. Until a more complete textbook is written, the reader who wishes to obtain a thorough knowledge of nuclear theory will have to consult the original literature, or for certain topics the articles of the present author in Reviews of Modern Physics (Vol. 8, p. 83, 1936; Vol. 9, pp. 69 and 245, 1937). The emphasis in this book is placed on the problem of nuclear forces. This problem is the central problem of nuclear physics. The problem is treated entirely from the empirical point of view, and I have made an effort to present the evidence available on nuclear forces from the behavior of the simplest nuclear systems. Purely theoretical considerations about nuclear forces, particularly the meson theory of these forces, are treated with the greatest brevity, because they are not yet in a form in which they would permit useful predictions. As a second field of nuclear physics which is sufficiently well developed and fundamental, I have chosen the theory of beta disintegration. The theory of the compound nucleus and its consequences for the prediction of the probabilities of nuclear reactions I have treated only very briefly. The reason for this was partly a matter of time: the lecture course on which these chapters are based contained only twenty lectures, and it seemed more profitable to treat part of the theory thoroughly than to treat all of it superficially. Partly, however, the brevity of treatment of the more com-phcated nuclei was purposeful; in the last ten years the workers in this field have shown an inclination to devote a large proportion of their effort to the study of the complicated nuclei, and the danger exists that the right perspective may be forgotten. The wartime research in the atomic energy project tended further to emphasize the usefulness of the predictions from the theory of the