https://doi.org/10.1351/goldbook.A00536
An atom or group which, when added to or introduced into a @[email protected], causes a bathochromic shift and/or a @[email protected] in a given band of the @[email protected], usually in that of lowest frequency. This term is obsolete.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2229 [Terms] [Paper]