Allowed and forbidden character in the π* <-- n band in symmetric alkyl ketones
Abstract
The polarized excitation spectra using the T1( nπ*) → S 0 emission, and oscillator strengths of π * ← n for several symmetric alkyl ketones have been measured. The interpretation of the excitation spectra assumes that the triplet state is distorted and that the T1 → S0 emission has a transition moment up to 35° out-of-the average molecular plane and along the C dbnd O bond in the triplet state conformation. The results indicate that the formaldehyde vibronic mechanism dominates except where adjacent carbon atoms to the carbonyl carbon provide a low symmetry field, as in diisopropyl or dicyclohexylketones. The hydrogen atoms seem to play only a minor role in giving electronically allowed character to π * ← n .
- Publication:
-
Journal of Molecular Spectroscopy
- Pub Date:
- October 1970
- DOI:
- 10.1016/0022-2852(70)90130-X
- Bibcode:
- 1970JMoSp..36..141C