Photoacoustic spectrum of iodine in the 490-680-nm (20402-14700-cm(-1)) region.
Vibronically resolved laser photoacoustic spectra of I(2) vapor have been recorded at room temperature in the presence and absence of atmospheric air in the 490-680 nm (20402-14700 cm(-1)) region for what is, to our knowledge, the first time. The vibrational bands belong to the B(3)Pi(O(u)(+)) ? X(1)Sigma(g)(+) transition, but the underlying continuum also results from the (1)Pi(1u) ? X (1)Sigma(g)(+) and A (3)Pi(1u) ? X (1)aSigma(g)(+) transitions. The mechanisms of photoacoustic signal generation are discussed by analyzing the photoacoustic intensity in light of Franck-Condon factors for the B ? X transition. Energy transfer to O(2) caused by the photodissociation of I(2) into (2)P(?) + (2)P((1/2)) I atoms is obrved in the presence of atmospheric air, and the predissociation of the B state has been observed for its vibrational levels v' ~ 23-27.
Narayanan
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Thakur
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