Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and ...recombination governed plasmas used for studies of recombination of KrD+ and H3+ ions.
We observed an increase in the effective recombination coefficient (
α
eff) of the recombination of H
3
+ ions with electrons with a number density of
H
2,
n(
H
2)
. With increasing
n(H
2) from 1×10
...11 to
2×10
12
cm
−3
the
α
eff increased from 1.3×10
−8 to
1.5×10
−7
cm
3
s
−1
. The dependence of
α
eff on
n(H
2) indicates that the recombination of H
3
+ ions in an afterglow plasma is a complex process in which collisions with H
2 take place. It is stressed that at conditions corresponding to plasma in interstellar space the dissociative recombination of H
3
+ ions is very slow with a rate coefficient
α⩽1.3×10
−8
cm
3
s
−1
.
Measurements of recombination rate coefficients of binary and ternary recombination of
and
ions with electrons in a low temperature plasma are described. The experiments were carried out in the ...afterglow plasma in helium with a small admixture of Ar and parent gas (H
2
or D
2
). For both ions a linear increase of measured apparent binary recombination rate coefficients (α
eff
) with increasing helium density was observed: α
eff
= α
BIN
+ K
He
He. From the measured dependencies, we have obtained for both ions the binary (α
BIN
) and the ternary (K
He
) rate coefficients and their temperature dependence. For the description of observed ternary recombination a mechanism with two subsequent rate determining steps is proposed. In the first step, in
+ e
−
(or
+ e
−
) collision, a rotationally excited long-lived Rydberg molecule
(or
) is formed. In the following step
(or
) collides with a He atom of the buffer gas and this collision prevents autoionization of
(or
). Lifetimes of the formed
(or
) and corresponding ternary recombination rate coefficients have been calculated. The theoretical and measured binary and ternary recombination rate coefficients obtained for
and
ions are in good agreement.
Results of an experimental study of binary recombination of para- and ortho-
ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest ...rotational states of
ions in the temperature range of 77–200 K in an
-dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure
and
. The results are in good agreement with previous theoretical predictions.
Results of an experimental study of binary recombination of para- and ortho- ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest ...rotational states of ions in the temperature range of 77-200 K in an -dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure and . The results are in good agreement with previous theoretical predictions.
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