In this monograph we describe an important and relatively new class of phenomena in the field of high-resolution atomic spectroscopy: the interference effects manifest in the angular distribution and polarization of spontaneous radiation and absorption by atoms. Although the quantum-theoretical descrip tion of these interference effects is quite subtle, it turns out - as so often in quantum mechanics - that a simple classical or semi-classical description offers much insight and can even explain quantitative features. In this presentation, however, we attempt to give the full story. Beginning with the simple semi classical description, we then present the quantum-mechanical analysis based on the density-matrix formalism and the statistical tensor. The remaining two chapters discuss experimental observations and data analysis. A great variety of effects have now been observed and can be used to obtain highly accu rate information about hyperfine structure, atomic constants, interaction con stants, etc. The authors have assumed only a basic knowledge of quantum mechanics and electromagnetism, thus making the book accessible to those beginning a graduate studies program. It is also aimed at practising spectroscopists and all researchers for whom atomic spectroscopy is an important tool - for these readers it will hopefully offer some new solutions and ideas for furthering their research. February 1993 E. B. Alexandrov M. P. Chaika G. I. Khvostenko Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2. Classical Description of Interference Phenomena in Radiation 2. 1 The Classical Oscillator Model of Atomic Emission . .
|Publisher:||Springer Berlin Heidelberg|
|Series:||Springer Series on Atomic, Optical, and Plasma Physics , #7|
|Edition description:||Softcover reprint of the original 1st ed. 1993|
|Product dimensions:||6.10(w) x 9.25(h) x 0.02(d)|
Table of Contents1. Introduction.- 2. Classical Description of Interference Phenomena in Radiation.- 2.1 The Classical Oscillator Model of Atomic Emission.- 2.2 A Classical Oscillator in a Magnetic Field.- 2.3 Emission from an Oscillator in a Magnetic Field.- 2.4 Emission from an Ensemble of Oscillators.- 2.5 Beats in Intensity.- 2.6 The Hanle Effect.- 2.7 Combination of Hanle Effect and Quantum Beats.- 2.8 Beat Resonances.- 2.9 Parametric Resonance.- 2.10 Conclusion.- 3. Quantum Mechanical Description of Interference Phenomena.- 3.1 The Density Matrix.- 3.2 Derivation of the Density Matrix of Ensembles of Excited States from the Wave Equation.- 3.3 The Equation of Motion of the Density Matrix.- 3.4 Spontaneous Emission.- 3.5 Limits of the Density Matrix Apparatus. The Scattering Matrix.- 3.6 Interference Signals.- 3.7 The Radiation Pattern and Polarization for Transitions Between Eigenstates of the Angular Momentum Operator.- 3.8 Influence of Interference Between States on the Polarization of Spontaneous Radiation.- 3.9 Redistribution of Radiated Energy Due to the Interference of Quantum States.- 3.10 Some Results from the Formalism of Irreducible Tensor Operators.- 3.11 Radiation Polarization in the Statistical Tensor Formalism Comparison of the Conclusions of Quantum Mechanical and Classical Approaches.- 3.12 Biaxial Alignment.- 3.13 Level Anti-crossings.- 3.14 Interference Phenomena in Magnetic Resonance.- 3.15 Application of Interference Signals.- 4. Experimental Observation of Interference Signals.- 4.1 Basic Experimental Scheme.- 4.2 Ensembles of Particles.- 4.3 Techniques for Inducing Coherence.- 4.4 Observation of Interference Phenomena.- 4.5 Hanle Effect in Atoms in the Ground State.- 4.6 Manifestation of the Interference of States in Collisions.- 4.7 Quantum Beats upon Pulse Excitation.- 4.8 Coherent Resonances.- 4.9 Other Resonances.- 4.10 Self-Alignment of Atomic States in a Plasma.- 4.11 Hidden Alignment.- 4.12 Self-Orientation.- 4.13 Interference of Atomic States in Astrophysics.- 4.14 Cascaded Transitions.- 4.15 Diffusion of Radiation.- 4.16 Influence of the Laboratory Magnetic Field on the Hanle Signal Shape. False Hanle Signals.- 4.17 Spectral Content of the Exciting Light and Absorption Line Profile.- 4.18 Faraday Rotation.- 4.19 Hanle Effect Due to Excitation That Is Random with Time.- 4.20 Polarization of Atomic Fluorescence in a Flame.- 4.21 Detection of the Polarization Moments by Radioactivity.- 4.22 Use of the Polarization Moments for Improving the Accuracy of Nonlinear Spectroscopic Techniques.- 4.23 Conclusion.- 5. Calculation of Interference Signals.- 5.1 An Atom in a Magnetic Field.- 5.2 The Hyperfine Structure.- 5.3 The Magnetic Dipole Interaction Constant.- 5.4 Quadrupole Interaction Between a Nucleus and an Electron Shell.- 5.5 Transition Matrix Elements of the Electric Dipole Moment.- 5.6 Eigenpolarizations of Transitions.- 5.7 Matrix Elements of the Dipole Transition Between States with Hyperfine Structure.- 5.8 The Stark Effect.- 5.9 Atoms with Nonzero Nuclear Spin in External Fields.- 5.10 Perturbation Operators and Their Matrix Elements.- 5.11 The Zeeman Effect in Atoms with Hyperfine Structure.- 5.12 The PaschenBack Effect.- 5.13 Hyperfine Splitting in a Weak Magnetic Field.- 5.14 The Stark Effect in Atoms with Hyperfine Structure in a Weak Electric Field.- 5.15 The Stark Effect in Atoms with Hyperfine Structure in Intermediate Fields.- 5.16 Splitting of Atomic Levels with Hyperfine Structure in a Strong Electric Field.- 5.17 Behaviour of Atoms in Combined Fields.- References.