Substituent effects in benzene cation spectroscopy. II. Photodissociation spectra of methylbenzene ions
- 1 April 1978
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 68 (7) , 3133-3138
- https://doi.org/10.1063/1.436155
Abstract
Photodissociation spectra have been obtained for the complete series of methylbenzene cations. The spectra are similar in pattern, showing a visible peak and a uv peak, and the positions, widths, and intensities of the peaks are reported for all 13 ions. The peak positions, and to some extent intensities, are discussed in terms of the perturbation expressions derived in the preceding paper. Substituent effects on the visible peak positions are reasonbly well accounted for by the simplest first‐order inductive perturbation model. However, the uv peak positions are in extreme disagreement with the predictions of this simplest model. It is shown that second‐order perturbations can account for nearly all of the uv peak shifts, and a successful quantitative model is described, although the complexity of possible second‐order effects precludes any definitive conclusion about the uv peak situation.Keywords
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