Occurs in emission sources of finite thickness when
radiant energy quanta emitted by atoms (or molecules) are absorbed by atoms of the same kind present
in the same source. The absorbed energy is usually dissipated by collisional transfer
of energy, or through emission of
radiant energy of the same or other frequencies. In consequence, the observed
radiant intensity of a spectral line (or band component) emitted by a source may be less than the
radiant intensity would be from an optically thin source having the same number of emitting atoms.
Self-absorption may occur in all emitting sources to some degree, whether they are
homogeneous or not.
Source:
PAC, 1996, 68, 2223
(Glossary of terms used in photochemistry (IUPAC Recommendations 1996))
on page 2273
PAC, 1994, 66, 2513
(Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994))
on page 2525
See also:
PAC, 1982, 54, 1533
(Glossary of terms used in nuclear analytical chemistry (Provisional))
on page 1552
PAC, 1985, 57, 1453
(Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation
sources (Recommendations 1985))
on page 1464