Spectroscopy at Radio and Microwave Frequencies

1. Introduction.- 1.1 The nature of spectroscopy.- 1.2 The concept of energy levels.- 1.3 The electromagnetic spectrum.- 1.4 Methods of spectroscopy.- 1.5 The microwave region.- 1.6 Gaseous spectroscopy.- 1.7 Solid state spectroscopy.- 1.8 Ferromagnetic resonance.- 1.9 Free radicals and F-centres.- 1.10 Measurements at radiofrequencies.- 2. The Production and Detection of Microwaves.- 2.1 Introduction.- 2.2 Velocity modulation.- 2.3 Practical microwave sources.- 2.4 Automatic tuning.- 2.5 Other sources of radiation.- 2.6 Detection of the radiation-silicon crystals.- 2.7 Different detecting systems.- 2.8 Display systems.- 2.9 Measurement of frequency.- 3. Waveguide Techniques.- 3.1 Propagation of radiation in waveguides.- 3.2 Choice of waveguide size.- 3.3 Circular guides.- 3.4 Coupling into waveguides. Directional couplers.- 3.5 Matching techniques.- 3.6 Crystal holders.- 3.7 Microwave bridge balancing.- 3.8 Cavity resonators. Wavemeters.- 3.9 Absorption cavities.- 3.10 Waveguide cells.- 4. Microwave Spectroscopes.- 4.1 General considerations.- 4.2 Line widths in gaseous spectroscopy-natural line width-the Doppler effect-pressure broadening-wall collisions-power saturation broadening-modulation broadening.- 4.3 Early gaseous microwave spectroscopes-Stark modulation-source modulation.- 4.4 Recent gaseous spectroscopes-mm-wavelength spectroscope-high resolution gaseous spectroscope.- 4.5 Comparison of sensitivities-superheterodyne detection -Stark and source modulation-crystal video detection.- 4.6 Special spectroscopes. Zeeman effect.- 4.7 Measurement of line shapes and intensities.- 4.8 Paramagnetic resonance. Solid state spectroscopy- natural line width-spin-lattice relaxation-spin-spin interaction-exchange interaction-power saturation broadening-inhomogeneous fields-summary.- 4.9 Early paramagnetic resonance experiments.- 4.10 Typical paramagnetic resonance spectroscopes- crystal-video-superheterodyne detection-source modulation.- 4.11 Gaseous paramagnetic spectroscopes.- 4.12 Comparison of sensitivities.- 4.13 The production and measurement of magnetic fields.- 4.14 Low-temperature technique.- 5. Results and Theory of Gaseous Spectroscopy.- 5.1 Introduction-water vapour-oxygen.- 5.2 Molecular energy levels.- 5.3 Linear molecules.- 5.4 Symmetric-top molecules.- 5.5 Asymmetric-top molecules.- 5.6 Inversion spectra.- 5.7 Hindered rotation.- 5.8 Stark and Zeeman effects-Introduction.- 5.9 Stark effect-linear molecules-symmetric-top molecules- asymmetric-top molecules-inversion spectra.- 5.10 The Zeeman effect.- 5.11 Nuclear interaction and hyperfine structure-electric quadrupole interaction-two-nuclei quadrupole interaction- nuclear octopole moment-magnetic hyperfine structure.- 6. Results and Theory of Paramagnetic Resonance.- 6.1 Introduction.- 6.2 The transition elements.- 6.3 The effect of internal crystalline fields.- 6.4 The resonance condition.- 6.5 Nuclear interaction and hyperfine structure.- 6.6 Second-order effects and quadrupole interaction.- 6.7 The theoretical Hamiltonian.- 6.8 Angular variation-electronic transitions-hyperfine structure.- 6.9 The iron group. Effect of crystalline fields.- 6.10 General results from the iron transition group- electronic transitions-hyperfine structure.- 6.11 Results for individual ions of the first transition group.- 6.12 Covalent compounds.- 6.13 The rare-earth group. General results.- 6.14 Results for different ions of the rare-earth group.- 6.15 Results from the palladium transition group.- 6.16 Results for the platinum group.- 6.17 Results from the trans-uranic group.- 6.18 Paramagnetic resonance and other low-temperature measurements.- 6.19 Paramagnetic resonance in gases.- 6.20 Conclusion.- 7. Ferromagnetic Resonance. Free Radicals and F-Centres.- 7.1 Introduction-ferromagnetic resonance-paramagnetic resonance in free radicals-electron resonance from metals and semi-conductors-paramagnetic resonance absorption in F-centres.- 7.2 Ferromagnetic resonance. Initial work.- 7.3 Further experiments in ferromagnetic resonance.- 7.4 The theoretical treatment of ferromagnetic resonance -g-values-line widths.- 7.5 Antiferromagnetic resonance.- 7.6 Paramagnetic resonance in systems other than the transition elements.- 7.7 Resonance in free radicals.- 7.8 Resonance from broken bonds.- 7.9 Resonance from conduction electrons.- 7.10 Electron resonance in semi-conductors-resonance from donor atoms in silicon-cyclotron resonance in germanium.- 7.11 Paramagnetic resonance from F-centres.- 7.12 Summary.- 8. Radiofrequency Spectroscopy.- 8.1 The resonance condition.- 8.2 Molecular beam experiments-steady field deflexion methods-radiofrequency resonance techniques-initial results from the resonance method-recent work on molecular beams.- 8.3 Atomic beams and the determination of the free electron gyromagnetic ratio-the hyperfine structure anomaly-the determination of quadrupole moments- determination of the gyromagnetic ratio of the free electron.- 8.4 Initial solid state experiments.- 8.5 The techniques of nuclear resonance.- 8.6 The techniques of nuclear induction.- 8.7 Pulse and echo methods-nutational resonance-spin echo method.- 8.8 Results of nuclear paramagnetic experiments- results from liquids-results from metals-results from crystals-other frequency shifts in nuclear resonance.- 8.9 Pure quadrupole nuclear resonance-initial work- later results-experimental technique.- 8.10 The interaction of electron and nuclear resonance. The Overhauser effect.- 8.11 Electron resonance at radiofrequencies.- 9. Applications of Radiofrequency and Microwave Spectroscopy.- 9.1 Introductory review.- I: Applications to Fundamental Research.- 9.2 Nuclear spins-determinations by paramagnetic resonance -determination by gaseous spectroscopy-determination by nuclear resonance.- 9.3 Nuclear magnetic moments-from nuclear resonance- from paramagnetic resonance-determinations from gaseous spectroscopy.- 9.4 Nuclear quadrupole moments.- 9.5 Nuclear alignment-low-temperature methods-paramagnetic resonance and nuclear alignment-results of low-temperature experiments-nuclear alignment by direct resonance techniques.- 9.6 The determination of chemical parameters-determinations from gaseous spectroscopy-determinations from paramagnetic resonance-determinations from nuclear resonance.- II: Applications of a Practical Nature.- 9.7 Frequency standards and the measurement of time- gaseous microwave standards-atomic beam frequency standards.- 9.8 The measurement of magnetic fields-nuclear resonance-electron resonance-nuclear precession-stabilization of magnetic fields by resonance methods.- 9.9 Chemical analysis-by gaseous spectroscopy-by paramagnetic resonance.- 9.10 The detection of free radicals.- 9.11 The study of irradiation damage.- 9.12 Other applications-radio astronomy-study of conduction bands in metals and semi-conductors-photochemical reactions-study of gas discharges.- Author Index.