A process by which a particle in the
ground state or an
excited state may undergo transition to a higher energy level by
absorption of a photon. For a given particle in the lower state of
probability per second of such a transition in a field with a continuous spectrum is proportional
to the
spectral radiant energy density of the
absorption line. The proportionality constant is termed the transition
probability for absorption. The transition
probability for
stimulated emission is defined in a similar way for the reverse
radiative de-excitation process that is induced by the same radiation field.
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.
https://doi.org/10.1351/goldbook.
