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Spectroscopy of Defects in Organic Crystals presents a masterly summary of the widespread and voluminous literature on the subject, presenting theoretical and experimental investigations of electron and vibronic optical spectra of organic crystals. Electronic states of defects combine to form crystal near-to-band and band levels. These are discrete states in the vicinity of exciton bands, surface and dislocational excitons, etc. Some studies have expressed dissimilar or even conflicting opinions about the nature of observed phenomena. In the choice of the material, preference has been given to phenomena which have received a theoretical interpretation. Some attention is paid to observations which are not completely understood and also to effects predicted but not yet confirmed.
The monograph will be useful for scientists as well as undergraduate and postgraduate students of solid state physics.
List of contents
1 Theory of Local Excitons.- 1.1 Basic Concepts of the Exciton Theory.- 1.2 Isotopic Impurity Spectrum.- 1.3 Local Excitons (X-Traps).- 1.4 Calculations of the Green Functions.- 1.5 Light Absorption by Local Excitons.- 1.6 Models of Local Exciton Centers (X-Traps).- 1.7 Vibronic Spectra of Local Excitons.- 2 Optical Spectra and Models of Local Excitons.- 2.1 Spectra of Local Excitons in Naphthalene and Deuteronaphthalene Crystals.- 2.2 Spectra of Local Excitons in Benzene.- 2.3 Experimental Data Analyses Model of Local Center.- 2.4 Configurational Mixing Effects for Local Excitons in Naphthalene Crystals.- 2.5 Optical Spectra of Naphthalene in the Region of Vibronic Transitions.- 2.6 Vibronic Spectra with Non-Totally Symmetric Vibrations in Naphthalene Doped with Heterocyclic Impurities.- 2.7 Vibronic Spectra with Totally Symmetric Vibrations.- 2.8 Local Excitons and Charge Transfer States.- 2.9 Influence of Concentration Effects on Local Exciton Spectra.- 2.10 Defects and Exciton-Band States.- 2.11 Local States in Crystals with Wide Exciton Bands.- 2.12 Triplet Local Excitons.- 2.13 Electron-Phonon Interaction in Local Centers.- 2.14 Creation of Local Centers by Irradiation.- 2.15 Appendix.- 3 Optical Spectra of Strained Organic Crystals.- 3.1 Deformation of Crystals under Stress.- 3.2 Exciton Hamiltonian of Strained Crystals.- 3.3 Optical Spectra under Hydrostatic Pressure.- 3.4 Exciton Spectra under Uniaxial Stress.- 3.5 Impurity Levels under Uniaxial Stress.- 3.6 Vibronic Levels in Strained Crystals.- 3.7 Excitations in Strained Naphthalene.- 3.8 Observation of Uniaxial-Stress Effects.- 3.9 Exciton Deformation Potential.- 3.10 Prospects of Uniaxial-Stress-Effect Investigations.- 4 Dislocations and Optical Properties of Organic Crystals.- 4.1 Observation of Dislocations in Luminescence Spectra.- 42 Dislocational Excitons in Strongly Anisotropic Crystals.- 43 Light Absorption by Dislocational Excitons.- 44 Light Scattering by Dislocations in the Region of Exciton Absorption.- 45 Excitation Energy Migration in Crystals with Dislocations and Local Centers.- 5 Surface Excitons.- 5.1 Quasiparticles in a Finite Crystal.- 5.2 Energy Spectrum of Surface Excitons.- 5.3 Quantization of Excited States of a Finite Crystal in Presence of the Electromagnetic Field.- 5.4 Electrodynamics of Surface Excitons.- 5.5 Light Reflection from Crystals with Narrow Bands.- 5.6 Observations of Surface Excitons in Reflection Spectra.- 5.7 Luminescence of Surface Excitons.- 5.8 Surface States in Vibronic Spectra.- 5.9 Excitation of Surface Excitons by Electron Beams.- 6 Thermoluminescence Spectroscopy of Defects.- 6.1 Trap Spectroscopy by Glow Technique.- 6.2 Dipole Traps for Charge Carriers.- 6.3 Dipole-Trap Clusters in Anthracene.- 6.4 Hydronaphthile Radicals - Deep Traps in Pure Naphthalene.- 6.5 Tautomers in Crystals of Nucleic Acid Bases.- 6.6 Temperature and Exciton Density Auto-Oscillations in Crystals under the Light Excitation.- References.- Author index.
