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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.32: Poster
Wednesday, April 4, 2001, 12:30–15:00, AT3
Stationary afterglow study of recombination of H3+ ions with electrons — •Juraj Glosik, Radek Plasil, Viktoriya Poterya, Pavel Kudrna, Andriy Pysanenko, Milan Tichy, and Jan Rusz — Charles University Prague, Mathematics and Physics Faculty, Department of Electronics and Vacuum Physics, V Holesovickach 2, 180 00 Prague 8, Czech Republic
The rate coefficient of the recombination of H3+ ions with electrons, α, has been measured at 270 K in stationary afterglow experiment. Strong dependence of an apparent recombination rate coefficient, αeff, on the number density of added neutral H2, n(H2), was obtained. At high number densities, n(H2) > 5×1012 cm−3 the apparent rate of the recombination is approaching value αeff ∼ 2×10−7 cm3s−1. With decreasing n(H2) down to 6×1010 cm−3 the observed recombination rate coefficient is decreasig down to αeff LIMIT < 4×10−9 cm3s−1. The obtained nearly linear dependence of αeff on n(H2) can indicate that the H3+ ions are removed from the plasma in a three body process. We assume that in the first step of this process the highly excited H3* is formed in collision of H3+ ions with electrons. The recombination process is completed by collison of H3* with present H2 which prevents autoionisation of H3* back to ion and electron.
The actual, for interstellar space relevant, No-dqbinaryNo-dq recombination rate coefficient α < αeff LIMIT = 4×10−9 cm3s−1. This is in the agreement with theoretical predictions and recent astronomical observations.