Electronic state distribution of Xe+* formed by excitation transfer from He(2 3S) to Xe+(2P3/2) at thermal energy

Abstract

The formation process of Xe+* in the He afterglow reaction of Xe has been studied by observing Xe ii lines in the ultraviolet and visible regions. Sixty one Xe+* states in the 13.86–19.49 eV range were excited by the He(2 3S)+Xe+(5p5 2P03/2) excitation-transfer reaction. It was found that Xe+* was not formed by the He(2 3S)+Xe(6s 3P02) Penning type reaction and the He++Xe(6s 3P02) charge-transfer reaction. There were some unclassified Xe ii lines, which occupied 14% of the total production of Xe+*. Most of them were attributed to Xe+ transitions from unknown high energy Xe+* states in the 18–19.5 eV range. The electronic state distribution of individual Xe+* levels has been determined by taking account of radiative cascade for low lying electronic levels. The He(2 3S)+Xe+(2P03/2) reaction expressed no resonant character. The electronic state of Xe+* was distributed more widely than those of Ar+* and Kr+* in the He(2 3S)+Ar+(3p5 2P03/2), He(2 3S)+Kr+(4p5 2P01/2), and He(2 3S)+Kr+(4p5 2P03/2) reactions. The excitation mechanism of rare gas cations due to collisions between a rare gas metastable atom and a rare gas ion is discussed. The lack of the excitation processes of Kr+* and Xe+* by the He++Kr(3P02) and He++Xe(3P02) reactions was attributed to the absence of near-resonant Kr+(5p) and Xe+(6p) states whose excitation satisfies the selection rule of Δl=±1.

Photochemically Induced Electronic-To-Electronic Energy Transfer in Geminate CO···O van der Waals Pair Generated through Vacuum Ultraviolet Photolysis of CO2 in Ar Matrices

“…In the course of time, photoinduced EET has become an important aspect of photophysics ,− and photochemistry. − EET processes are observed in the gas phase, , in the fluid-phase, in molecular crystals, in liquid crystals, and more recently, in low-temperature matrices. − These processes involve electronic (E), vibrational (V), and rotational (R) EET, namely, E → E, E → V, V → E, and V → R. To the best of our knowledge there has been no systematic spectroscopic study that deals with photochemically induced E → E EET, which will be presented here.…”

“…In the course of time, photoinduced EET has become an important aspect of photophysics 4,[13][14][15] and photochemistry. [16][17][18] EET processes are observed in the gas phase, 9,19 in the fluidphase, 6 in molecular crystals, 20 in liquid crystals, 21 and more recently, in low-temperature matrices.…”

Photochemically Induced Energy Transfer II: Spectroscopic and Photophysical Aspects of the Electronic-to-Electronic Energy Transfer in Geminate van der Waals Complexes

“…Several terminologies have been used in the literature to account for this type of EET, for example: formation of excited intermediates, [10][11][12] nonvertical and nonspectroscopic energy transfer, 13,14 non-Franck-Condon, nonresonant and nonoptical energy transfer, 15-17 crossing of the entrance and product channels. 18 An interesting aspect of the nonresonant EET, however, is that in the majority of cases involvement of an excited complex has been postulated. We have recently observed such a nonresonant EET in (O‚‚‚CO) van der Waals complex mediated through the formation of excited CO 2 .…”

“…Though the resonant EET processes outlined above seem to be better understood, the understanding of the nonresonant EET processes has been more diffuse. Several terminologies have been used in the literature to account for this type of EET, for example: formation of excited intermediates, − nonvertical and nonspectroscopic energy transfer, , non-Franck−Condon, nonresonant and nonoptical energy transfer, − crossing of the entrance and product channels . An interesting aspect of the nonresonant EET, however, is that in the majority of cases involvement of an excited complex has been postulated.…”