A3Π1u ← X1Σg + laser photoacoustic spectroscopy of Br2 vapor in the extreme red wavelength region 665-720 nm

Abstract

The A3Π1u ← X 1Σg+ photoacoustic spectrum of Br 2 vapor has been studied and vibronic analysis performed using earlier data available for this system of bands from optical spectroscopy in the region 665-720nm. The vibronic levels involved in these transitions are 4≦v′≦21 and 1≦v″≦4. The relative photoacoustic intensities of the vibronic bands have been used in estimating the non-radiative relaxation rate from vibrational levels of A3Π1u state. The non-radiative relaxation is found to be a nonlinear function of the upper state vibrational quantum number. The radiative rate constants for the A3Π1u state vibrational levels have been compared with the corresponding non-radiative constants obtained from present work. Non-radiative decay rate constants for the vibrational levels of A 3Π1u state have been experimentally determined for the first time from photoacoustic spectrum of Br2 vapor in the extreme red region. © 2003 Published by Elsevier B.V.