Temperature dependence of binary and ternary recombination of H{sub 3}{sup +} ions with electrons

Journal Article · Fri May 15 04:00:00 EDT 2009 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.79.052707· OSTI ID:21304692

Glosik, J; Plasil, R; Korolov, I; Kotrik, T; Novotny, O; Hlavenka, P; Dohnal, P; Varju, J; Kokoouline, V; Greene, Chris H ^[1]

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1. Mathematics and Physics Faculty, Charles University, Prague 8 (Czech Republic)

We study binary and the recently discovered process of ternary He-assisted recombination of H{sub 3}{sup +} ions with electrons in a low-temperature afterglow plasma. The experiments are carried out over a broad range of pressures and temperatures of an afterglow plasma in a helium buffer gas. Binary and He-assisted ternary recombination are observed and the corresponding recombination rate coefficients are extracted for temperatures from 77 to 330 K. We describe the observed ternary recombination as a two-step mechanism: first, a rotationally excited long-lived neutral molecule H{sub 3}* is formed in electron-H{sub 3}{sup +} collisions. Second, the H{sub 3}* molecule collides with a helium atom that leads to the formation of a very long-lived Rydberg state with high orbital momentum. We present calculations of the lifetimes of H{sub 3}* and of the ternary recombination rate coefficients for para- and ortho-H{sub 3}{sup +}. The calculations show a large difference between the ternary recombination rate coefficients of ortho- and para-H{sub 3}{sup +} at temperatures below 300 K. The measured binary and ternary rate coefficients are in reasonable agreement with the calculated values.

• OSTI ID: 21304692
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 79; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AFTERGLOW
ATOMS
BUFFERS
ELECTRON TEMPERATURE
ELECTRON-MOLECULE COLLISIONS
ELECTRONS
HELIUM
HYDROGEN IONS 3 PLUS
LEAD
MOLECULES
PLASMA
RECOMBINATION
ROTATIONAL STATES
RYDBERG STATES
TEMPERATURE DEPENDENCE