Photoacoustic Spectroscopic Studies of Mono-Substituted Naphthalene Molecules |
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Authors: | R K Garg Pardeep Kumar R S Ram Z H Zaidi |
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Institution: | 1. National Physical Laboratory , Dr. K.S. Krishnan Marg, New Delhi , 110012 , India;2. Physics Department , Jamia Millia Islamia , New Delhi , 110025 , India |
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Abstract: | The present paper deals with the Photoacoustic (PA) studies of mono-substituted (hydroxy) naphthalene molecules, namely 1-naphthol and 2-naphthol in boric acid glass in the region 250–400 nm. The electronic transitions of these molecules observed experimentally, have been interpreted using the optimised geometries and CNDO/S-CI method. Assignments of observed electronic transitions are made on the basis of singlet-singlet and singlet-triplet transitions. The PA spectra of 1-naphthol and 2- Maphthol are compared with its parent molecule i.e. naphthalene molecule, in terms of charge transfer character of -OH group and polarization of molecules. It is observed that the non-radiative transitions in mono-substituted naphthalene molecules shift towards the higher wavelength region when compared with naphthalene molecule, which may be attributed to increase in the charge density in the substituted ring. |
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Keywords: | Photoacoustic Spectroscopy Polycyclic aromatic hydrocarbons Naphthols Singlet-Triplet Transitions CNDO Calculations |
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