The probability that an atomic spectroscopic transition will occur is called the transition probability or transition strength. This probability will determine the extent to which an atom will absorb light at a resonance frequency, and the intensity of the emission lines from an atomic excited state. The spectral width of a spectroscopic transition depends on the widths of the initial and final states. The width of the ground state is essentially a delta function and the width of an excited state depends on its lifetime. Specific Documents

- Transition strengths
- Excited-state lifetime and the natural linewidth
- Transition lineshapes and broadening

- Atomic absorption spectroscopy
- Atomic emission spectroscopy
- Atomic fluorescence spectroscopy