| Abstract: | The electronic transitions of di-hydroxy naphthalene molecules are found to be shifted towards higher wavelength side, when hydroxyl groups are substituted in the naphthalene molecule. The changes in the position and intensity of the electronic bands depend upon the charge transfer property of the substituent. The present paper correlates the electronic transitions observed in the photoacoustic spectra of naphthalene, 1,3-dihydroxy naphthalene (DHN), 1,4-DHN and 1,5-DHN in the region 250–400 nm. The electronic transitions of these molecules have been interpreted using the optimised geometries and CNDO/S-CI methods. Assignments of the observed electronic transitions are made on the basis of radiative and non-radiative transitions. A good agreement is found between the experimental and calculated results. |
