Self-Trapped Excitons discusses the structure and evolution of the self-trapped exciton (STE) in a wide range of materials. It includes a comprehensive review of experiments and extensive tables of data. Emphasis is given throughout to the unity of the basic physics underlying various manifestations of self-trapping, with the theory being developed from a localized, atomistic perspective. The topics treated in detail in relation to STE relaxation include spontaneous symmetry breaking, lattice defect formation, radiation damage, and electronic sputtering.

Inhalt

1 Introduction.- 1.1 Excitons.- 1.1.1 One-Electron Band State.- 1.1.2 Exciton State.- 1.1.3 Absorption Spectr.- 1.1.4 Luminescence Spectra.- 1.2 Charge Carriers and Excitons in a Deformable Lattice.- 1.2.1 Polarons.- 1.2.2 Self-Trapping in a Continuum Model.- 1.2.3 The Electron-Hole System in a Deformable Lattice.- 1.2.4 Exciton-Phonon Coupling Constant from the Urbach Edge.- 1.3 Scope of this Monograph.- 2 Investigation of Self-Trapped Excitons from a Defect Perspective.- 2.1 Atomistic Structure of Self-Trapped Carriers.- 2.1.1 Self-Trapped Holes.- 2.1.2 Self-Trapped Electrons.- 2.2 Self-Trapped Excitons.- 2.3 Experimental Methods.- 2.3.1 Transient Optical Absorption and Emission.- 2.3.2 Photoconversion Spectroscopy.- 2.3.3 Synchrotron Radiation Studies.- 2.3.4 Optically Detected Magnetic Resonance.- 2.4 Theoretical Methods.- 2.4.1 Extended-Ion Approximation.- 2.4.2 Semi-Empirical Methods.- 2.4.3 Hartree-Fock Cluster Methods.- 3 Condensed Rare Gases.- 3.1 Electronic Structure.- 3.2 Spectroscopy.- 3.2.1 Luminescence.- 3.2.2 Transient Absorption.- 3.2.3 Photoconversion Spectroscopy.- 3.2.4 Surface STE States.- 3.3 Theory of the Self-Trapped Exciton in Rare-Gas Solids.- 3.3.1 Method Based on ab initio Ne*-Ne Potentials.- 3.3.2 Extended-Ion Approaches.- 3.3.3 Other Approaches.- 3.4 Desorption from the Surface.- 4 Alkaline Earth Fluorides.- 4.1 Electronic Structure.- 4.2 Lattice Defects.- 4.3 Theory of Self-Trapped Excitons in Fluorite Crystals.- 4.3.1 Extended-Ion Calculations for CaF2 and SrF2.- 4.3.2 Zero-Field Splitting of the Triplet STE.- 4.4 Spectroscopy.- 4.5 Lattice Defect Formation.- 5 Alkali Halides.- 5.1 Material Properties.- 5.2 Theory of Self-Trapped Exciton Structure.- 5.2.1 The STE as (Vk + e).- 5.2.2 Lattice Relaxation for the (Vk + e) Model.- 5.2.3 The Off-Center STE.- 5.2.4 ab initio Hartree-Fock Cluster Calculation of STE Structure.- 5.3 Luminescence.- 5.3.1 Survey of Luminescence Spectra.- 5.3.2 ?-Polarized Bands.- 5.3.3 Zero-Field Splitting and Triplet Sublevel Decay Kinetics.- 5.3.4 ?-Polarized Bands.- 5.3.5 Band Positions.- 5.3.6 Band Shape.- 5.3.7 Pressure and Dilatation Effects.- 5.3.8 Excitation Spectra.- 5.4 Magneto-Optics, ODMR, and ODENDOR.- 5.4.1 Magnetic Circular Polarization.- 5.4.2 Optically Detected Magnetic Resonance.- 5.4.3 Optically Detected Electron Nuclear Double Resonance.- 5.5 Excited-State Absorption.- 5.5.1 Characteristic Features and Binding Energies.- 5.5.2 Photoconversion and Polarization Analysis.- 5.6 Resonant Raman Scattering.- 5.7 Dynamics.- 5.7.1 Conversion of Excitons from Free to Self-Trapped States.- 5.7.2 Hole Self-Trapping Dynamics.- 5.7.3 STE Formation from Free Carriers and Relaxation from Excited States.- 5.7.4 Hot Luminescence of Self-Trapped Excitons.- 5.8 Kinetics.- 5.8.1 Quenching of STE Luminescence.- 5.8.2 Diffusion of Self-Trapped Excitons.- 6 Defect Formation in Alkali Halide Crystals.- 6.1 Self-Trapped Excitons as Nascent Defect Pairs.- 6.2 Thermally Activated Conversion.- 6.2.1 Primary Defect Formation versus Stabilization.- 6.2.2 Diffusion of the H Center from the STE.- 6.3 Dynamic Conversion Process.- 6.3.1 The Rabin-Klick Diagram.- 6.3.2 Time-Resolved Studies.- 6.3.3 Dynamic Mechanisms.- 6.4 Stabilization of the Primary Defects.- 6.5 Defects and Desorption at Surfaces.- 6.5.1 Desorption Induced by Excitonic Processes.- 6.5.2 Atomic Force Microscopy.- 6.5.3 Defect Processes in Alkali Halide Clusters.- 7 Silicon Dioxide.- 7.1 Material Properties.- 7.1.1 Crystal Structure.- 7.1.2 Electronic Structure.- 7.2 Theory of Self-Trapped Excitons.- 7.2.1 Semiempirical (INDO) Approach.- 7.2.2 ab initio Approach.- 7.3 Experiments on Crystalline SiO2.- 7.3.1 Luminescence.- 7.3.2 Optically Detected Magnetic Resonance.- 7.3.3 Transient Absorption, Volume Change, and Photoconversion Spectroscopy.- 7.4 Experiments on Amorphous SiO2.- 7.5 Self-Trapped Holes in SiO2.- 7.6 Defect Generation Processes.- 8 Simple Organic Molecular Crystals.- 8.1 Material Properties.- 8.2 Pyrene.- 8.3 Anthracene.- 8.4 Perylene.- 9 Silver Halides.- 9.1 Electronic Structure and Exciton Spectra.- 9.2 Self-Trapped Hole in AgCl.- 9.2.1 Optical Transitions.- 9.2.2 The Self-Trapping Barrier and Hole Transport.- 9.3 Self-Trapped Exciton in AgCl.- 9.3.1 Optical Transitions.- 9.3.2 Optically Detected Magnetic Resonance.- 9.3.3 AgBr and the AgBr1-XC1X Alloy System.- 10 As2Se3 and Other Chalcogenides.- 10.1 Structure and Electronic States of As2Se3.- 10.2 The Self-Trapped Exciton.- 10.3 Spectroscopy.- 10.4 STE to Defect Conversion in Amorphous Chalcogenides.- 10.5 Spectroscopy in Crystalline Trigonal Selenium.- 11 Other Materials, Extrinsic Self-Trapping, and Low-Dimensional Systems.- 11.1 Ammonium Halides.- 11.2 KMgF3 and Related Perovskites.- 11.3 Alkaline-Earth Fluorohalides.- 11.4 Alkali Silver Halides.- 11.5 LiYF4.- 11.6 Extrinsic Self-Trapping in ZnSeTex.- 11.7 Quasi-One-Dimensional Systems.- References.