دانلود کتاب An Introduction to Molecular Spectra (with 8 plates and 151 text diagrams)

An Introduction to MOLECULAR SPECTRA by RAYNOR C. JOHNSON. PREFACE THE student of atomic spectra has many books at his disposal the student of molecular spectra has but few at present. This is to be expected in view of the greater complexity of the latter, and that its theoretical development came later. I have attempted to provide a text-book for the student who has graduated in Physics or Chemistry or who is approaching graduation and desires an understanding of the subject within the limits of ordinary mathematical equipment at that stage. Thus, at one or two points I have introduced the results of wave-mechanics, but I have not assumed familiarity in the use of this method. Again, in dealing with the electronic structures of polyatomic molecules, J have considered it outside the scope of the present book to introduce matters involving a knowledge of Group Theory. In preparing a book of this kind the author is indebted for diagrams and illustrative material to the original papers of many workers who have contributed to the advancement of the subject. Wherever possible permission has been obtained from either author or publisher, and acknowledgement of the source is made in the text. No writer on molecular spectra can fail to record his indebtedness to Prof. R. S. Mullikens outstanding contributions to the subject. In addition to this I particularly desire to thank Dr. W. Jevons, whose Report on Band Spectra of Diatomic Molecules, published by the Physical Society in 1932, has proved of the utmost help. I am grateful also to Dr. F. A. Jenkins for the use of several of his fine grating spectra, and to Miss I. Arnott for her secretarial assistance. B. c. JOHNSON December, CONTENTS PAGE I. INTRODUCTION 1 a The energy of atoms and molecules. b The general structure of band systems. c The fine structure of bands. d Infra-red band spectra. II. THE GROSS STRUCTURE OF BAND SYSTEMS 15 a Representation of bands. 6 The interval between band head and origin. c The assignment of vibrational quantum numbers. d The origin of multiplicity in band heads. e Formation of tails in band sequences. III. THE DISTRIBUTION OF INTENSITY IN A SYSTEM 31 a The Franck-Condon theory. 6 Some typical intensity distributions. c Intersection of U r curves Pre-dissociation. d Variability in intensity distributions. e Considerations based on wave-mechanics. Continuous spectra. IV. THE INTER-NUCLEAR LAW OF FORCE 50 a The V r function of Kratzer. b The U r function of Morse. c The U r function of Rydberg. d Some empirical relations between molecular con stants. e The vibrational-rotational interaction. V. THE DISSOCIATION OF MOLECULES 59 a General principles. b The ionic type of binding. c The atomic type of binding homopolar . d The Van der Waals type of binding. e The 0 v w v relation Birges second method. Dissociation through rotation. AN INTRODUCTION TO MOLECULAR SPECTRA PAGE VI. THE ELECTRONIC STATES OF MOLECULES 79 a The correlation of band systems of a molecule. b Description of the electronic states of atoms. 0 0 Description of the electronic states of molecules selection rules. d Detailed electronic configurations. e Hcitlcr and Londons method. The method of Hund, Herzberg, and Mulliken. g Valency. VII. ROTATIONAL TERMS AND VECTOR COUPLINGS 95 a Hunds Case a. b Hunds Case b. c Hunds Case 6. d Stages intermediate between a and 6. e Hunds Case c. Hunds Case d. g A-type doubling. VIII. FINE STRUCTURE GENERAL CONSIDERA TIONS 105 a Types of branches. b Positive and negative rotational levels. c The combination principle. IX. THE FINE STRUCTURE OF TYPICAL BANDS 110 X...