1. Binary and ternary recombination of para-H3+ and ortho-H3+ with electrons: State selective study at 77-200 K.
- Author
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Dohnal, Petr, Hejduk, Michal, Varju, Jozef, Rubovicˇ, Peter, Roucˇka, Sˇteˇpán, Kotrík, Tomásˇ, Plasˇil, Radek, Glosík, Juraj, and Johnsen, Rainer
- Subjects
ELECTRONS ,HYDROGEN plasmas ,NUCLEAR spin ,LOW temperatures ,ABSORPTION spectra ,RECOMBINATION (Chemistry) ,PHYSICAL & theoretical chemistry - Abstract
Measurements in H
3 + afterglow plasmas with spectroscopically determined relative abundances of H3 + ions in the para-nuclear and ortho-nuclear spin states provide clear evidence that at low temperatures (77-200 K) para-H3 + ions recombine significantly faster with electrons than ions in the ortho state, in agreement with a recent theoretical prediction. The cavity ring-down absorption spectroscopy used here provides an in situ determination of the para/ortho abundance ratio and yields additional information on the translational and rotational temperatures of the recombining ions. The results show that H3 + recombination with electrons occurs by both binary recombination and third-body (helium) assisted recombination, and that both the two-body and three-body rate coefficients depend on the nuclear spin states. Electron-stabilized (collisional-radiative) recombination appears to make only a small contribution. [ABSTRACT FROM AUTHOR]- Published
- 2012
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