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|Type:||Artigo de periódico|
|Title:||High Resolution Phosphorescence Emission Studies On Para-substituted Acetophenones At 1.6 K|
|Abstract:||The phosphorescence emission spectra of acetophenone, p-chloroacetophenone, p-bromoacetophenone, p-methoxyacetophenone and p-thiomethoxyacetophenone in p-dimethoxybenzene host crystal at 1.6 K are recorded under high resolution. Detailed vibronic analyses of the emission spectra are carried out and a one dimensional Franck-Condon calculation is performed. Lifetime and optical polarization measurements for the phosphorescence emission of the acetophenone derivatives are also determined. The results lead to the conclusion that the lowest triplet state of acetophenone is n,π* in character with a non-planar configuration resulting from a distortion along the nontotally symmetric vibration of -COCH3 and -CH3 wags. Emission spectra from the lowest triplet states of p-methoxyacetophenone and p-thiomethoxyacetophenone are found to originate from π,π* states and have a planar geometry. The phosphorescence spectra of p-chloroacetophenone and p-bromoacetophenone are from a 3(π,π*) state but have a large amount of n,π* mixed character. The vibrations responsible for such mixing are assigned to the nontotally symmetric modes of -COCH3, -Br and -Cl wags. © 1976.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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