absorptance, \(\alpha\)

Ratio of the absorbed to the incident @R05046@. Also called @A00039@. When \(\alpha \leq 1\), \(\alpha \approx A_{\text{e}}\), where \(A_{\text{e}}\) is the Napierian @A00028@.
Green Book, 2nd ed., p. 32 [Terms] [Book]
See also:
PAC, 1985, 57, 105. (Names, symbols, definitions and units of quantities in optical spectroscopy (Recommendations 1984)) on page 114 [Terms] [Paper]
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2226 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 959 [Terms] [Paper]