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Photophysics of Gaseous UF6 in the UV: Energy Balance Through Quantum Efficiency Measurements

1979; Springer Science+Business Media; Linguagem: Inglês

10.1007/978-3-642-67254-5_13

2364-9003

Olivier De Witte, R. Dumanchin, J.P. Gauyacq, M. Michon, M. Alexandre,

Atmospheric Ozone and Climate

Experimental results were recently published on the fluorescence of gaseous UF6 excited in the near UV by a tunable dye laser [1, 2, 3, 4, 5, 6]. Several features of this fluorescence are now well established. The visible fluorescence spreads from 400 to 460 nm with a maximum around 420 nm: the shape of the spectrum is independent of pressure or of wavelength of excitation [4, 6]. The Stern-Volmer plot has a saturation like behaviour for the high pressures [4, 5]. This result although found on the experimental points in [2, 3] was not taken into account by Benetti and Andreoni. The excitation spectrum of fluorescence drops down below 380 nm to give almost no emission for an excitation below 360 nm [1, 4, 6]. We give here a systematic study of absolute quantum yieds of fluorescence of UF6. After a description of the experimental apparatus we study the effects of three parameters on the quantum efficiency and decay times: room temperature self quenching, temperature effects between 20° C and 100° C and collisions with rare gas. All these results are taken in account in a tentative phenomenological model presented at the end.