High-resolution dissociative recombination of cold H3+and first evidence for nuclear spin effects.
The energy-resolved rate coefficient for the dissociative recombination (DR) of H(3)(+) with slow electrons has been measured by the storage-ring method using an ion beam produced from a radiofrequency multipole ion trap, employing buffer-gas cooling at 13 K. The electron energy spread of the merged-beams measurement is reduced to 500 microeV by using a cryogenic GaAs photocathode. This and a previous cold- measurement jointly confirm the capability of ion storage rings, with suitable ion sources, to store and investigate H(3)(+) in the two lowest, (J,G) = (1,1) and (1,0) rotational states prevailing also in cold interstellar matter. The use of para-H(2) in the ion source, expected to enhance para-H(3)(+) in the stored ion beam, is found to increase the DR rate coefficient at meV electron energies.
Kreckel
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Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
Motsch
M
M
Mikosch
J
J
Glosík
J
J
Plasil
R
R
Altevogt
S
S
Andrianarijaona
V
V
Buhr
H
H
Hoffmann
J
J
Lammich
L
L
Lestinsky
M
M
Nevo
I
I
Novotny
S
S
Orlov
D A
DA
Pedersen
H B
HB
Sprenger
F
F
Terekhov
A S
AS
Toker
J
J
Wester
R
R
Gerlich
D
D
Schwalm
D
D
Wolf
A
A
Zajfman
D
D