luminescence which occurs essentially only during the irradiation of a substance by electromagnetic radiation.
Sources:
PAC, 1984, 56, 231. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy' on page 233 (https://doi.org/10.1351/pac198456020231)
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2519 (https://doi.org/10.1351/pac199466122513)