National Institute of Standards and Technology
Gaithersburg, Maryland 20899

1. Introduction
2. Frequency, Wavenumber, Wavelength
3. Atomic States, Shells, and Configurations
4. Hydrogen and Hydrogen-like Ions
5. Alkalis and Alkali-like Spectra
6. Helium and Helium-like Ions; LS Coupling
7. Hierarchy of Atomic Structure in LS Coupling
8. Allowed Terms of Levels for Equivalent Electrons 
   
   • LS Coupling  
   • jj Coupling  
9. Notations for Different Coupling Schemes 
   
   • LS Coupling (Russell-Saunders Coupling)  
   • jj Coupling of Equivalent Electrons  
   • J₁ j or J₁ J₂ Coupling  
   • J₁ l or J₁ L₂ Coupling (J₁ K Coupling)  
   • LS₁ Coupling (LK Coupling)  
   • Coupling Schemes and Term Symbols  
10. Eigenvector Composition of Levels
11. Ground Levels and Ionization Energies for the Neutral Atoms
12. Zeeman Effect
13. Term Series, Quantum Defects, and Spectral-line Series
14. Sequences 
    
    • Isoelectronic Sequence  
    • Isoionic, Isonuclear, and Homologous Sequences  
15. Spectral Wavelength Ranges, Dispersion of Air
16. Wavelength (Frequency) Standards
17. Spectral Lines: Selection Rules, Intensities, Transition Probabilities, Values, and Line Strengths 
    
    • Emission Intensities (Transition Probabilities)  
    • Absorption f values  
    • Line Strengths  
    • Relationships between A, f, and S  
    • Relationships between Line and Multiplet Values  
    • Relative Strengths for Lines of Multiplets in LS Coupling  
18. Atomic Lifetimes
19. Regularities and Scaling 
    
    • Transitions in Hydrogenic (One-Electron) Species  
    • Systematic Trends and Regularities in Atoms and Ions with Two or More Electrons  
20. Spectral Line Shapes, Widths, and Shifts 
    
    • Doppler Broadening  
    • Pressure Broadening  
21. Spectral Continuum Radiation 
    
    • Hydrogenic Species  
    • Many-Electron Systems  
22. Sources of Spectroscopic Data
23. References