Introduction to Chemical Physics Book

INTRODUCTION TO CHEMICAL PHYSICS BY J. C. SLATER Professor of Physics Massachusetts Institute of Technology FIRST EDITION SEVENTH IMPRESSION McGRAW-HILL BOOK COMPANY, INC. NEW YORK AND LONDON 1939 PYRK8HT, 1939, BY TIIK i BOOK COMPANY, INC. PRINTED IN THE UNITED STATES OP AMERICA All rights reserved. This book, or parts thereof, may not be reproduced in any form without permission of the publishers. THE MAPLE PRESS COMPANY, YORK, PREFACE It is probably unfortunate that physics and chemistry over were separated. Chemistry is the science of atoms and of the way they com bine. Physics deals with the interatomic forces and with the large-scale properties of matter resulting from those forces. So long as chemistry was largely empirical and nonmathematical, and physics had not learned how to treat small-scale atomic forces, the two sciences seemed widely separated. But with statistical mechanics and the kinetic theory on the one hand and physical chemistry on the other, the two sciences began to come together. Now that statistical mechanics has led to quantum theory and wave mechanics, with its explanations of atomic interactions, there is really nothing separating them any more. A few years ago, though their ideas were close together, their experimental methods were still quite different chemists dealt with things in test tubes, making solutions, pre cipitating and filtering and evaporating, while physicists measured every thing with galvanometers and spectroscopes. But even this distinction has disappeared, with more and more physical apparatus finding its way into chemical laboratories. A wide range of study is common to both subjects. The sooner we realize this the better. For want of a better name, since Physical Chemistry is already preempted, we may call this common field Chemical Physics. It is an overlapping field in which both physicists and chemists should be trained. There 4 seems no valid reason why their training in it should differ. This book is an attempt to incorporate some of the material of this common field in a unified presentation. What should be included in a discussion of chemical physics Logi cally, we should start with fundamental principles. We should begin with mechanics, then present electromagnetic theory, and should work up to wave mechanics and quantum theory. By means of these w r e should study the structure of atoms and molecules. Then we should introduce thermodynamics and statistical mechanics, so as to handle large collections of molecules. With all this fundamental material we could proceed to a discussion of different types of matter, in the solid, liquid, and gaseous phases, and to an explanation of its physical and chemical properties in terms of first principles. But if we tried to do all this, we should, in the first place, be writing several volumes which would include almost all of theoretical physics and chemistry and in the second place no one but an experienced mathematician could handle the vi PREFACE theory. For both of these reasons the author has compromised greatly in the present volume, so as to bring the material into reasonable com pass and to make it intelligible to a reader with a knowledge of calculus and differential equations, but unfamiliar with the more difficult branches of mathematical physics. In the matter of scope, most of the theoretical physics which forms a background to our subject has been omitted. Much of this is considered in the companion volume, Introduction to Theoretical Physics, by Slater and Frank. The effort has been made in the present work to pro duce a book which is intelligible without studying theoretical physics first. This has been done principally for the benefit of chemists and others who wish to obtain the maximum knowledge of chemical physics with the minimum of theory. In the treatment of statistical mechanics only the most elementary use of mechanics is involved...Read More