| Autor: |
Mitsuo Ito, Masayo Yamauchi, Masaaki Fujii, Ken Takazawa |
| Rok vydání: |
1994 |
| Předmět: |
|
| Zdroj: |
Spectrochimica Acta Part A: Molecular Spectroscopy. 50:1421-1433 |
| ISSN: |
0584-8539 |
| DOI: |
10.1016/0584-8539(94)e0052-c |
| Popis: |
The S 1 ← S 0 fluorescence excitation spectra and the S 1 → S 0 dispersed fluorescence spectra of o -, m -and p -tolunitrile were measured in supersonic jets. Low-frequency bands due to internal rotation of the methyl group were observed in m - and p -tolunitrile. Observed band positions and relative intensities of the internal rotational bands were reproduced by a calculation using a free rotor basis set. From the analysis, the potential curve of the internal rotation was determined in both S 1 and S 0 . It was found that the barrier height increases in going from S 0 to S 1 in m -tolunitrile, while it decreases in p -tolunitrile. In contrast, no low-frequency band was found in o -tolunitrile. It is concluded that the potential curve in o -tolunitrile does not change in going from S 0 to S 1 . The change of the barrier height by electronic excitation in tolunitriles differs greatly from that observed in other toluene derivatives. It is suggested that the electronic properties of a substituent are important for the methyl rotation in the excited state. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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