Radiative and non-radiative transitions of 1,5-dihydroxy anthraquinone molecule

Anthraquinone derivatives are found to be useful as prototype for synthesiz ing a class of antivirals, against HIV type 1 in primary human lymphocytes. These molecules have been studied for the last several years by using conv entional spectroscopy. Recently. some polycyclic aromatic hydrocarbons mole cules have been studied by a recent non-destructive technique known as Phot oacoustic (PA) spectroscopy. In the present study. electronic transitions o f 1.5-dihydroxy anthraquinone molecule are reported using PA and optical ab sorption spectra in boric acid glass in the region 250-400 nm, The electron ic transitions of these molecules observed experimentally. have been interp reted using the optimized geometry and CNDO/S-C1 method. A good agreement i s found between the experimental and calculated results. Assignments of obs erved electronic transitions are made on the basis or singlet-singlet and s inglet-triplet transitions. Vibrations attached to these electronic transit ions ars attributed Lo the ground state vibrational modes.