Rotational cooling of HD+ molecular ions by superelastic collisions with electrons.
Merging an HD+ beam with velocity matched electrons in a heavy ion storage ring we observed rapid cooling of the rotational excitations of the HD+ ions by superelastic collisions (SEC) with the electrons. The cooling process is well described using theoretical SEC rate coefficients obtained by combining the molecular R-matrix approach with the adiabatic nuclei rotation approximation. We verify the DeltaJ=-2 SEC rate coefficients, which are predicted to be dominant as opposed to the DeltaJ=-1 rates and to amount to (1-2)x10;{-6} cm;{3} s;{-1} for initial angular momentum states with J< or =7, to within 30%.
Shafir
D
D
Department of Particle Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
Novotny
S
S
Buhr
H
H
Altevogt
S
S
Faure
A
A
Grieser
M
M
Harvey
A G
AG
Heber
O
O
Hoffmann
J
J
Kreckel
H
H
Lammich
L
L
Nevo
I
I
Pedersen
H B
HB
Rubinstein
H
H
Schneider
I F
IF
Schwalm
D
D
Tennyson
J
J
Wolf
A
A
Zajfman
D
D