The breadth of scientific and technological interests in the general topic of photochemistry is truly enormous and includes, for example, such diverse areas as microelectronics, atmospheric chemistry, organic synthesis, non-conventional photoimaging, photosynthesis, solar energy conversion, polymer technologies, and spectroscopy. This Specialist Periodical Report on Photochemistry aims to provide an annual review of photo-induced processes that have relevance to the above wide-ranging academic and commercial disciplines, and interests in chemistry, physics, biology and technology. In order to provide easy access to this vast and varied literature, each volume of Photochemistry comprises sections concerned with photophysical processes in condensed phases, organic aspects which are sub-divided by chromophore type, polymer photochemistry, and photochemical aspects of solar energy conversion. Volume 34 covers literature published from July 2001 to June 2002. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.
Photochemistry Volume 6
A Review of the Literature Published between June 1973 and June 1974
By D. Bryce-SmithThe Royal Society of Chemistry
Copyright © 1975 The Chemical Society
All rights reserved.
ISBN: 978-0-85186-055-8Contents
Introduction and Review of the Year By D. Bryce-Smith, iii,
Books on Photochemistry, xi,
Part I Physical Aspects of Photochemistry,
Chapter 1 Spectroscopic and Theoretical Aspects By D. Phillips, 3,
Chapter 2 Developments in Instrumentation and Techniques By M. A. West, 62,
Chapter 3 Photophysical Processes in Condensed Phases By K. Salisbury, 115,
Chapter 4 Gas-phase Photoprocesses By D. Phillips, 196,
Part II Photochemistry of Inorganic and Organometallic Compounds By J. M. Kelly,
1 Introduction, 259,
2 Photochemistry of Metal Ions and Co-ordination Compounds, 259,
3 Water, Hydrogen Peroxide, and Anionic Species, 301,
4 Main-group Elements, 304,
Part III Organic Aspects of Photochemistry,
Chapter 1 Photolysis of Carbonyl Compounds By W. M. Horspool, 313,
Chapter 2 Enone Cycloadditions and Rearrangements: Photoreactions of Cyclohexadienones and Quinones By W. M. Horspool, 348,
Chapter 3 Photochemistry of Olefins, Acetylenes, and Related Compounds By W. M. Horspool, 400,
Chapter 4 Photochemistry of Aromatic Compounds By A. Gilbert, 449,
Chapter 5 Photo-oxidation and -reduction By H. A. J. Carless, 509,
Chapter 6 Photoreactions of Compounds containing Heteroatoms other than Oxygen By S. T. Reid, 552,
Chapter 7 Photoelimination By S. T. Reid, 616,
Part IV Polymer Photochemistry By D. Phillips,
1 Introduction, 659,
2 Photopolymerization, 659,
3 Photophysical and Photochemical Properties of Polymers, 671,
4 Photodegradation of Polymers, 683,
5 Photodisposable Plastics, 696,
6 Stabilization of Polymers against U.V. Degradation, 697,
7 Photochemistry of Dyes; Tendering, 706,
8 Photodegradation of other Organic Materials, 707,
9 Appendix: Review of Patent Literature, 708,
Part V Photochemical Aspects of Solar Energy Conversion By M. D. Archer,
1 Introduction, 739,
2 The Conversion of Light into Chemical Free Energy, 743,
3 Aspects of Photovoltaic Power Conversion of Relevance to Chemistry, 757,
4 Photobiological Considerations, 761,
5 Photochemical Syntheses that Might be Carried out using Solar Energy, 763,
Errata, 765,
Author Index, 766,
CHAPTER 1
Part I
PHYSICAL ASPECTS OF PHOTOCHEMISTRY
1
Spectroscopic and Theoretical Aspects
BY D. PHILLIPS
1 Introduction
The format for presentation of this section is as in previous years. Attempts have been made this year to reduce the length of the volume, so although coverage of significant new work is believed to be complete, detailed discussion of individual papers is more selective.
2 MO Calculations
All papers discussed under this section are concerned with calculations of energy levels and transition energies. A criterion for Gaussian approximations of Slater-type orbitals, multi-configuration SCF theory for excited states, spin-restricted open-shell SCF theory, and complex MO's in the extended HF scheme have been presented. A one-electron model has been used with some success to predict singlet- and triplet-state energy differences in helium and carbon monoxide, results being within 15% of observed values. The method thus permits reasonable estimation of triplet levels from more easily observed singlet levels. Experimental energy levels of helium have also been compared with values calculated using a method of autocorrelation fields. Theoretical transition probabilities for electronic transitions in beryllium, first-row neutral and singly and doubly ionized atoms, and for the SiI 3s23p23P-3s5p33 D0 isoelectronic sequence in PII, ClIV, CaVII, and FeXIII have been obtained and compared with experimental values.
The use of the CNDO method in spectroscopy has been illustrated with respect to doublet states, and electronic quadrupole moments of excited states have been computed. A simple new function which can be used to represent the intermolecular pair potential energy of the noble gases has been proposed, and this can be compared with the excited state Ar + Xe (3P1) potential obtained from solvent shifts of the vacuum-u.v. spectrum of xenon in gaseous argon. Recent experiments involving microwave optical magnetic resonance induced by electrons (MOMRIE) on the d(3p)3IIu states of ortho- and para-H2 and -D2 have revealed discrepancies in measured fine-structure parameters, which are inexplicable in terms of the Born–Oppenheimer approximation. A general theory which can account for the observations has been presented.
SCF wavefunctions and energies for valence states and excited states of carbon and nitrogen have been discussed, and the momentum distribution in the [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [??] Σu+ states have been presented graphically and the results discussed. An exact numerical method for reducing eigenvalues of diatomic molecules to molecular parameters has been described for triplet states, particularly for those with Λ ≥ 2, such as the [??]3Δg and [??]3Φu states of N2 Dipole moments, induced dipole moments, and quadrupole moments for the [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [??]2Σ + states of CH have been calculated from accurate ab initio wavefunctions and potential curves. The oscillator strength for the [??]1Σ+ -> [??]2Π system in CH+ has been calculated as 0.001 (excitation energy 2.50 eV) by the equations of motion method. CI calculations on NO [??]2Π and [??]2Σ+ have been carried out but, at least for the [??]2Σ+ state, serious discrepancies were found between the theoretical and experimental values for the dipole moment and quadrupole coupling constant. Spectroscopic constants for the eight lowest electronic states of the NO+ ion have been tabulated. Several calculations on the iodine molecule potential curves, including analysis of the long-range RKR potential of the B3ΠOu+ state have been carried out. Unexpected effects concerning perturbations of the latter state have been discussed.
A number of papers presented during the past year have been concerned with calculations on triatomic species, and several of these have dealt with ozone. Thus ab initio SCF–CI calculations have shown that the ππ* singlet state of ozone has an unsymmetrical equilibrium geometry, with one long and one short O — O bond, and similar behaviour was proposed for the SO2 molecule. Theoretical evidence for strongly bent excited states of ozone has also been given by the same group. A comparison of INDO and ab initio methods for the corrected wavefunctions of ground and excited states of ozone has been carried out, and theoretical evidence for bound excited states of ozone has been presented. This indicates that the 3B2, 3A2, 1A2 and B1 states have binding energies of 0.4, 0.3, 0.1, and 0.0 eV, respectively, with respect to ground-state O2 and O. These results could be of importance if experiment verifies the existence of bound upper states, since ozone is of great...
