The change in the
internal energy of a particle may be due to radiative processes, i.e. the emission or absorption of a photon. A particle in an
excited state may undergo a transition to a lower energy level by emission of a photon. This is known as radiative de-excitation. If such a transition occurs spontaneously its
probability per second for a given excited particle is termed the transition
probability for
spontaneous emission.
Source:
PAC, 1985, 57, 1453
(Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985))
on page 1463
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
