https://doi.org/10.1351/goldbook.S05886
That @M03958@ of @E02056@ which occurs even in the absence of a perturbing external electromagnetic field. The transition between states, \(n\) and \(m\), is governed by the @E01914@ @C01124@ of spontaneous emission, \(A_{nm}\).
See also:
stimulated emission
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2277 [Terms] [Paper]