Measurement of the radiative lifetime of O-2(a(1)Delta(g)) using cavity ring down spectroscopy

Cavity ring down spectroscopy has been used to detect the weak a(1)Delta (g ) - X(3)Sigma (-)(g) electronic transition in oxygen and to obtain a measur ement of the radiative lifetime of the a(1)Delta (g) state. (0,0) band tran sitions near 1274 nm were scanned using the frequency-doubled output of a t unable OPO system. Pressure-broadened linewidths were measured, and a FWHM- broadening coefficient of 5.5(5) MHz/Torr was obtained. Analysis of the rin g down traces provided a measurement of the line strength of an individual rovibronic transition. The Einstein A-coefficient of the a(1)Delta (g) stat e was calculated using branching ratios determined from the Honl-London fac tors. The A-coefficient obtained is 2.3(3) x 10(-4) s(-1), corresponding to a radiative lifetime of 4300(500) s ( similar to 72 min). This value is in agreement with those reported by Badger et al. (2.58 x 10(-4) s(-1)) and S palek et al, (2.24(40) x 10(-4) s(-1)). In addition, a value of 2.77(8) x 1 0(-45) cm(5)/molecule was obtained for the background collisional absorptio n coefficient for oxygen at 1274 nm. Published by Elsevier Science Ltd.