The measurement of the absorption of
UV–VIS radiation by a solute in a highly viscous or solid matrix at low temperature.
Source:
PAC, 1988, 60, 1449
(Nomenclature, symbols, units and their usage in spectrochemical analysis - VII. Molecular
absorption spectroscopy, ultraviolet and visible (UV/VIS) (Recommendations 1988))
on page 1452