https://doi.org/10.1351/goldbook.B00618
Shift of a spectral band to lower frequencies (longer wavelengths) owing to the influence of substitution or a change in environment. It is informally referred to as a @R05211@ and is opposite to @H02929@ (@B00688@).
Sources:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1088 [Terms] [Paper]
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2230 [Terms] [Paper]