Electronic emission spectra of o- and m-fluorobenzaldehyde vapours

Abstract

The high resolution nπ* electronic emission spectra of o- and m-fluoro-benzaldehyde vapours in the region 365-560 nm excited in a discharge are reported for the first time. The spectra of both the compounds consist of the A 1 A″ -X 1 A′ fluorescence as well as the a 3 A″ -X 1 A′ phosphorescence bands. In the case of o-isomer, all the eleven out-of-plane vibrations have been observed in the fluorescence and the phosphorescence, though weakly in the latter, whereas in the case of m-isomer, only ten have been observed in the fluorescence and nine in the phosphorescence. It is found that the most intense bands in both the fluorescence and the phosphorescence spectra of these molecules belong to the trans-O rotamer. © 1993 Indian Academy of Sciences.