Atomic and Molecular Processes

Atomic and Molecular Processes describes radiative and collisional processes involving atoms or molecules. Organized into 21 chapters, this book emphasizes the developments in these processes stimulated by the growth of interest in space science, astrophysics, and plasma physics. The book initially discusses the general theory of magnetic dipole and electric quadrupole radiation and the calculations and observations on individual atoms, as well as the forbidden transitions. The text then explores general topics on forbidden and allowed lines and bands; photoionization; photodetachment; recombination and attachment; elastic and inelastic scattering of electron; and energy loss by slow electrons. Discussions on collision broadening of spectral features and encounters between atomic systems including range, energy loss, excitation, ionization, detachment, charge transfer, elastic scattering, mobility, diffusion, relaxation in gases, and chemical reactions are provided in other chapters. A chapter is devoted to the use of high-temperature shock waves, and accounts of other main experimental methods are given.

ContributorsPreface1. Forbidden Transitions 1. Introduction 2. Forbidden Lines in Atomic Spectra 3. Forbidden Transitions in Diatomic Molecular Spectra 4. Forbidden Transitions in Polyatomic Molecular Spectra 5. Forbidden Transitions in Crystals 6. Forbidden Transitions in Astrophysics References2. Allowed Transitions 1. Introduction 2. Basic Concepts and Formulae 3. Calculations of Atomic Line Strengths 4. Theory of Molecular Line Strengths 5. Measurements of Atomic Transition Probabilities 6. Measurements of Molecular Transition Probabilities References3. Photoionization Processes 1. Introduction 2. Experimental 3. Theoretical 4. Results References4. Photodetachment 1. Introduction 2. Negative Ion Energy States 3. Theoretical Considerations 4. Experimental Method for Photodetachment Studies 5. The H- Photodetachment Cross Section 6. Photodetachment Cross Sections for O-, S-, and C- 7. Photodetachment of Negative Molecular Ions 8. Formation of Negative Ions by Radiative Attachment 9. Atomic Electron Affinities References5. High-Temperature Shock Waves 1. Introduction 2. Hydrodynamic Considerations 3. Plane Shock Waves 4. High-Energy Cylindrical Shock Waves 5. Establishment of Equilibrium Plasmas 6. Experimental Verification of the Rankine-Hugoniot Relations in Conventional Shock Tubes 7. Shock-Heated Plasmas as Thermal Light Sources References6. Attachment and Ionization Coefficients 1. Electron Attachment 2. Ionization Coefficients 3. Attachment Coefficients References7. Electronic Recombination 1. Collisional-Radiative Recombination 2. Recombination Involving a Free-Bound Radiationless Transition 3. Experimental Studies References8. Ionic Recombination 1. Three Body 2. Two Body References9. Elastic Scattering of Electrons 1. Scattering by a Potential Field 2. Measurement of Collision Cross Sections 3. Scattering by Hydrogen Atoms 4. Scattering by Complex Atoms and Ions 5. Scattering by Molecules References10. The Motions of Slow Electrons in Gases 1. Introduction 2. Theory of Motion of Ions and Electrons in Gases 3. Diffusion and Drift 4. Equation of Continuity 5. Mean Loss of Energy in Elastic Encounters 6. The Distribution Function f(c) 7. The Ratio W/D 8. Measurement of Mean Energy Lost in an Encounter 9. Experimental Procedure 10. Experimental Results 11. The Losses of Energy by Electrons in Colliding with Gas Molecules References11. The Theory of Excitation and Ionization by Electron Impact 1. Classical Theory 2. General Quantum Theory 3. Partial Wave Theory 4. Calculated and Measured Cross Sections 5. Collisional Excitation Treated as a Radiative Process Appendix References12. The Measurement of Collisional Excitation and Ionization Cross Sections 1. Introduction 2. Electron Impact Studies 3. Ion Impact Studies 4. Neutral Impact Studies 5. Electron-Ion Collisions References13. Spectral Line Broadening in Plasmas 1. Introduction 2. Basic Considerations 3. The Impact Approximation 4. Applications of the Impact Approximation to Broadening by Electrons 5. Corrections to the Impact Approximation 6. Broadening by Ions 7. Comparison with Experiment References14. Theoretical Treatment of Collisions between Atomic Systems 1. First Born Approximation 2. Higher Approximations 3. Slow Collisions References15. Range and Energy Loss 1. Energy Loss of Charged Particles 2. Range of Charged Particles 3. Ionization by Charged Particles 4. Energy Loss of Electrons 5. Range of Electrons 6. Ionization by Electrons References16. Diffusion and Mobilities Introduction 1. Diffusion 2. Mobilities References17.