Time-resolved excitation spectra of xenon vapor in the 1500 Å region

✍ Scribed by M. Ghelfenstein; R. Lopez-Delgado; H. Szwarc

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 717 KB
• Volume: 49
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(77)80594-0

✦ Synopsis

Time-inteLgrated and time-resoIved excitation spectra, as well as fluorescence lifetimes, have been nieasured for xenon vapor as a function of pressure (for pure xenon as well as with different collision partners: krypton and helium), monitoring the 1700 A second continuum afterglow. Three very different decay components have been observed: (a) A short component with lifetimes of the order of 2 ns, which is attributed to emission from the upper vibrational levels of the Ot('Z;) state of Xef. (b) A iong component with 7 = 60 ns, corresponding to emission from thermally relaxed vibrational levels of the 1 u, O;(3 Zi) states of Xe:. No intervention of any Xe atomic excited species is invoked to explain the excitation and deactivation processes of Xez molecules for these two components of the fluorescence. (c) A very long component with lifetimes in the 150-500 ns range, having a broad -1000 cm-l -escitation band, centered at = 1470 A and showing a striking screening and self-absorption effect as well as a strong effect when the partial pressure of a collision partner (Kr, He) is increased. The mechanism of this last excitation is not yet very well understood.