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# THE INTERNAL ROTATION AND INVERSION MOTIONS OF THIOACEALDEHYDE IN ITS FIRST TRIPLET $a^{3}A^{\prime\prime}$ ELECTRONIC STATE

Please use this identifier to cite or link to this item: http://hdl.handle.net/1811/17722

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 Title: THE INTERNAL ROTATION AND INVERSION MOTIONS OF THIOACEALDEHYDE IN ITS FIRST TRIPLET $a^{3}A^{\prime\prime}$ ELECTRONIC STATE Creators: Moule, D. C.; Nino, A. Issue Date: 1988 Abstract: Thioacetaldehyde, CH3CHS displays a banded absorption spectrum at 615 nm which is attributed to the $T_{1}\leftarrow S_{o},\bar{a}^{3}A^{\prime\prime}\leftarrow X^{1}A^{\prime}$ electronic transition which arises through $n\rightarrow \pi^{\ast}$ excitation. The spectrum in the To region consists of a cluster of bands which was assigned to the activity of the methyl torsional mode $\mathcal{V}_{15}$. Substitution of deuterium for the aldehyde hydrogen produces an isotope shift which demonstrates that a strong coupling exists between the aldehyde wagging mode $\mathcal{V}_{14}$ and the methyl torsion $\mathcal{15}$ Ab initio SCF methods were used to generate the potential surface defined by 0(internal rotation) and a(hydrogen wagging) in both electronic states from which the potential $V(\theta,\alpha)$ was derived as a Fourier expansion. The band spectrum of $CH_{3}CHS$ was synthesized from the energy levels and Franck Condon factors of a two-dimensional torsional-inversion Hamiltonian in which the torsion and inversion motions were treated as $C_{3}$ and $C_{1}$ rotations respectively. URI: http://hdl.handle.net/1811/17722 Other Identifiers: 1988-TG-6