DISCUSSIONS OF THE FARADAY SOCIETY No. 35, 1963 THE STRUCTURE OF ELECTRONICALLY EXCITED SPECIES IN THE GAS-PHASE THE FARADAY SOCIETY Agents f o r the Society’s Publications: The Aberdeen University Press Ltd. Farmers Hall Aberdeen scotland@ The Faraday Society and Contributors, 1963 PUBLISHED . . . . 1963 PRINTED IN GREAT BRITAIN AT THE UNIVERSITY PRESS ABERDEENA GENERAL DISCUSSION ON THE STRUCTURE OF ELECTRONICALLY EXCITED SPECIES IN THE GAS-PHASE 2nd and 3rd April, 1963 A GENERAL DISCUSSION on The Structure of Electronically-Excited Species in the Gas Phase was held at Queen’s College, University of St. Andrews, Dundee, on the 2nd and 3rd April, 1963. The President, Prof. A. R. Ubbelohde, C.B.E., M.A., D.Sc., F.R.S., was in the Chair and about 135 members and others were present.Among the visitors from overseas were the following: Mr. F. A. Baker (Switzerland), Mr. U. Bonne (Germany), Dr. J. Colpa (Netherlands), Prof. J. B. Coon (U.S.A.), Dr. M. Daniels (Puerto Rico), Dr. D. W. Davies (Netherlands), Dr. E. de Boer (Netherlands), Dr. A. E. Douglas (Canada), Prof. D. A. DOWS, (U.S.A.), Dr. H. R. Gersmann (Netherlands), Dr. Y. Haven (Netherlands), Dr. and Mme. H. Hering (France), Dr. G. Herzberg (Canada), Mr. M. Horani (France), Dr. J. C. Lorquet (Belgium), Dr. E. L. Mackor (Netherlands), Prof. B. H. Mahan (U.S.A.), Prof. L. J. Oosterhoff (Netherlands), Prof. H. B. Palmer (U.S.A.), Dr. L. M. Raff (U.S.A.), Dr. D. A. Ramsay (Canada), Prof. and Mrs. B. Rosen (Belgium), Prof. R. M. Rosenberg (U.S.A.), Mme. J. Rostas (France), Prof.P. S. Skell (U.S.A.), Dr. B. R. Stein (Germany), Dr. G. Szasz (Switzerland), Miss J. A. van der Hoek (Netherlands), Dr. J. H. van der Waals (Netherlands), Dr. G. A. J. Voetelink (U. S . A.) . . .. .A GENERAL DISCUSSION ON THE STRUCTURE OF ELECTRONICALLY EXCITED SPECIES IN THE GAS-PHASE 2nd and 3rd April, 1963 A GENERAL DISCUSSION on The Structure of Electronically-Excited Species in the Gas Phase was held at Queen’s College, University of St. Andrews, Dundee, on the 2nd and 3rd April, 1963. The President, Prof. A. R. Ubbelohde, C.B.E., M.A., D.Sc., F.R.S., was in the Chair and about 135 members and others were present. Among the visitors from overseas were the following: Mr. F. A. Baker (Switzerland), Mr. U. Bonne (Germany), Dr. J. Colpa (Netherlands), Prof. J.B. Coon (U.S.A.), Dr. M. Daniels (Puerto Rico), Dr. D. W. Davies (Netherlands), Dr. E. de Boer (Netherlands), Dr. A. E. Douglas (Canada), Prof. D. A. DOWS, (U.S.A.), Dr. H. R. Gersmann (Netherlands), Dr. Y. Haven (Netherlands), Dr. and Mme. H. Hering (France), Dr. G. Herzberg (Canada), Mr. M. Horani (France), Dr. J. C. Lorquet (Belgium), Dr. E. L. Mackor (Netherlands), Prof. B. H. Mahan (U.S.A.), Prof. L. J. Oosterhoff (Netherlands), Prof. H. B. Palmer (U.S.A.), Dr. L. M. Raff (U.S.A.), Dr. D. A. Ramsay (Canada), Prof. and Mrs. B. Rosen (Belgium), Prof. R. M. Rosenberg (U.S.A.), Mme. J. Rostas (France), Prof. P. S. Skell (U.S.A.), Dr. B. R. Stein (Germany), Dr. G. Szasz (Switzerland), Miss J. A. van der Hoek (Netherlands), Dr. J. H. van der Waals (Netherlands), Dr. G.A. J. Voetelink (U. S . A.) . . .. .CONTENTS PAGE Twelfth Spiers Memorial Lecture-Determination of the Structures of Simple Poly- atomic Molecules and Radicals in Electronically Excited States. By G. Herzberg . . 7 Electron-Impact Spectroscopy. By Aaron Kuppermann and L. M. Roff. . . 30 Circular Dichroism of Dissymmetric ap-Unsaturated Ketones. By R. E. Ballard, S. F. Mason and G. W. Vane . . 43 Dipole Moments and Polarizabilities of Electronically Excited Molecules Through the Kerr Effect. By A. D. Buckingham and David A. Dows . . 48 Wave Functions of Excited States. By J. W. Linnett and 0. Sovers . . 58 Angular Correlation Diagrams for AH2-Type Molecules. By C . A. Coulson and A. H. Neilson . . 71 Intersection of Potential Energy Surfaces in Polyatomic Molecules. By G.Herzberg and H. C. Longuet-Higgins . . 77 Stereochemistry of Hydrocarbon Ions. By J. C. Lorquet . . 83 Electronic Absorption Spectra of HCO and DCO Radicals. By J. W. C. Johns, S. H. Priddle and D. A. Ramsay . . 90 Carbon Monoxide Flame Bands. By R. N. Dixon . . 105 Spectrum of the C3 Molecule. By L. Gausset, G. Herzberg, A. Lagerqvist and B. Rosen . . 113 Evidence for a Double-Minimum Potential in an Excited State of C102. By J. B. Coon, F. A. Cesani and C. M. Loyd . . 118 Absorption Spectrum of Sulphur Dioxide in the Vacuum Ultra-violet. andB. Rosen . . 124 Rotational Analysis of Bands of the 3800A System of SO2. . 127 Absorption Spectrum of Chlorine Dioxide in the Vacuum Ultra-violet. By C . M. Electronic Structure and Spectrum of the HC02 Radical.By T. E. Peacock, Rias- ur-Rahman, D. H. Sleeman and E. S. G. Tuckley . . 144 Absorption Spectra of the Hydrides, Deuterides and Halides of Group 5 Elements. By C. M. Humphries, A. D. Walsh and P. A. Warsop . . 148 Electronically Excited States of Ammonia. By A. E. Douglas . . 158 The 38208, Band System of Propynol. By J. C. D. Brand, J. H. CalIomon and J. K. G. Watson . . 175 Near-Ultra-violet Spectrum of Propenal. By J. C . D. Brand and D. G. Williamson 184 By I. Dubois By A. J. Merer . Humphries, A. D. Walsh and P. A. Warsop . 137 Polarization and Assignment of the 3700 8, Absorption Spectrum of the Tropyl Radical. By B. A. Thrush and J. Vapour. By K. K. Innes and L. E. Giddings, Jr. . 5 Spectrum of 7,4-Diazine . 192 J. Zwolenik . . 1966 CONTENTS PAGE Ionization and Dissociation Energies of the Hydrides and Fluorides of the First Row Elements in Relation to their Electronic Structures. By W. C. Price, T. R. Passmore and D. M. Roessler . . 201 GENERAL DrscussroN.-~r. J. €3. van der Walls, Dr. E. L. Mackor, Prof. A. D. Walsh, Dr. S. F. Mason, Dr. E. Charney, Prof. C. A. Coulson, Dr. J. W. Linnett, Dr. D. W. Davies, Mr. D. M. Hirst, Dr. A. H. Neilson, Dr. H. H. Greenwood, Dr. A. E. Douglas, Dr. G. Herzberg, Dr. J. C. Lorquet, Dr. I. M. Mills, Dr. B. A. Thrush, Dr. R. N. Dixon, Dr. J. C. Brand, Prof. P. S. Skell, Dr. J. K. G. Watson, Mr. A. J. Merer, Dr. T. E. Peacock, Dr. J. L. Duncan, Prof. W. C. Price, Dr. T. R. Passmore, Dr. J. M. Hollas, Prof. K. K. Innes, Dr. D. M. Roessler 212 Author Index . . . . . 240