CHEMICAL KINETICS EDITED BY C. H. BAMFORD

Transcription

1 CHEMICAL KINETICS EDITED BY C. H. BAMFORD M.A., Ph.D., Sc.D. (Cantab.), F.R.I.C, F.R.S. Campbell-Brown Professor of Industriell Chemistry, University of Liverpool AND C. F. H. TIPPER Ph.D. (Bristol), D.Sc. (Edinburgh) Senior Lecturer in Physical Chemistry, University of Liverpool VOLUME 3 THE FORMATION AND DECAY OF EXCITED SPECIES ELSEVIER PUBLISHING COMPANY AMSTERDAM - LONDON - NEW YORK 1969

2 Contents Preface Chapter 1 (C. S. BURTON AND W. A. NOYES, JR.) Effect of low energy radiation vn 1 1. INTRODUCTION 1 2. SURVEY OF THE PRIMARY EFFECTS OF ELECTROMAGNETIC RADIATION Sensitization by monatomic gases Photosensitization by mercury vapor Absorption by diatomic gases Absorption by polyatomic gases Dissociation into atoms and radicals Dissociation into complete molecules Rearrangements Summary of basic problems EXPERIMENTAL PROBLEMS DIFFERENT RADIATION TYPES. CONCLUSIONS 60 REFERENCES 63 Chapter 2 (G. HUGHES) Effect of high energy radiation 1. INTERACTION OF HIGH ENERGY RADIATION WITH MATTER Mechanism of energy loss Species produced in an irradiated System Time scale of events Comparison with photochemistry EXPERIMENTAL EVIDENCE FOR SPECIES PRESENT Ions and electrons Gaseous Systems Liquid Systems Solid Systems Free radicals ESR data Spectra Chemical inferences of radical production Excited molecules CONCLUSION 103 REFERENCES

3 X CONTENTS Chapter 3 (T. CARRINGTON AND D. GARVIN) The chemical production of excited states INTRODUCTION Distribution of reaction products over internal energy states Models of reaction Kinematic modeis Potential energy surfaces Reactions on a Single Potential surface Reactions involving morethan one Potential surface Correlation rules Rotational excitation VIBRATIONAL EXCITATION Atom- or group-transfer reactions Flash photolysis: molecular oxygen and hydroxyl Atom-molecule reactions studied in flow Systems: the hydrogen halide system Comparison of molecular oxygen and hydrogen halide excitation Excitation of alkali metal salts Distribution of excitation between the reaction products Four-center exchange reactions Combination reactions producing vibrational excitation Addition of hydrogen atoms to alkenes Addition and insertion reactions ofmethylene Combination of free radicals Excitation in decomposition reactions ELECTRONIC EXCITATION The radiative recombination of atoms Helium atom recombination Halogen recombination Association reactions of oxygen atoms Nitrogen atom recombination Recombination of atoms with excitation of the third body The radiative combination of an atom with a diatomic molecule O+NO =NO c O+CO = CO e O+SO = SO c H+NO = HNO" H+OH = H Atom transfer reactions A+BC-*AB e +C A+BC->AB+C e Transfer reactions in Systems of more than three atoms Complex chemiluminescent Systems Excitation of additives in active nitrogen Reaction of oxygen atoms with acetylene ROTATIONAL EXCITATION CHEMICAL LASERS 171 Acknowledgement 174 REFERENCES 174

4 CONTENTS XI Chapter 4 (A. B. CALLEAR AND J. D. LAMBERT) The transfer of energy between chemical species INTRODUCTION EXPERIMENTAL MEASUREMENT OF RELAXATION TIMES Acoustic methods Shock-tube methods Spectroscopic methods THEORETICAL CONSIDERATIONS The Landau-Teller theory General principles of wave-mechanical treatment Vibrational excitation The interaction potential Translational overlap Vibrational matrix elements Transition probability Tanczos' theory for polyatomic molecules Orientation and low-temperature effects Exact quantum mechanical treatment Conclusion VIBRATION-TRANSLATION TRANSFER Diatomic molecules Polyatomic molecules Mixtures VIBRATION-VIBRATION TRANSFER Intramolecular transfer of vibrational energy Intermolecular transfer of vibrational energy Ultrasonic dispersion in mixtures Spectroscopic evidence Theoretical discussion Mechanisms of vibrational excitation ROTATION-TRANSLATION TRANSFER ROTATION-VIBRATION TRANSFER ELECTRONIC-TRANSLATION AND ELECTRONIC-VIBRATION RELAXATION WITH AE < 1 ev General considerations Cross sections for energy transfer Spin-orbit relaxation in selenium Relaxation of atomic iron Spin-orbit relaxation of highly excited species Variation of cross-section with change in internal energy Relaxation of atomic iodine ELECTRONIC-VIBRATION AND ELECTRONIC-TRANSLATION ENERGY TRANSFER WITH J» 1 ev Quenching and excitation of atomic sodium Detection of vibrational excitation by infrared emission Theory of quenching ELECTRONIC-ELECTRONIC ENERGY TRANSFER Introduction 256

5 XII CONTENTS 10.2 Mercury sensitised fluorescence Electronic excitation transfer between inert gas atoms Cross-sections for electronic energy transfer Electronic excitation transfer in complex Systems APPLICATION TO REACTION KINETICS AND PHOTOCHEMISTRY Unimolecular reactions Energy distribution in chemical reactions CONCLUSION 268 REFERENCES 269