The dissociative recombination of cold polyatomic molecular ions measured at a storage ring

1997 ◽  
Author(s):  
O. Heber ◽  
L. H. Andersen ◽  
D. Kella ◽  
H. B. Pedersen ◽  
L. Vejby-Christensen ◽  
...  
Keyword(s):  
Storage Ring ◽  
Dissociative Recombination ◽  
Molecular Ions

scholarly journals Dissociative Recombination of Polyatomic Molecular Ions: Branching Ratios and Isotopic Effects

2000 ◽  
Vol 197 ◽  
pp. 265-271
Author(s):  
L. H. Andersen ◽  
O. Heber ◽  
D. Zajfman
Keyword(s):  
Storage Ring ◽  
Dissociative Recombination ◽  
Branching Ratios ◽  
Molecular Ions ◽  
Recombination Process ◽  
Hydrogen Atoms ◽  
Ion Storage ◽  
Isotopic Effects ◽  
Many Particles

The branching ratios for the dissociative recombination of various vibrationally cold polyatomic molecular ions have been measured using the ASTRID ion storage ring. The results show that many particles are ejected during the recombination process, and that isotopic effects exist when hydrogen atoms are replaced by deuterium.

Recombination of simple molecular ions studied in storage ring: dissociative recombination of H2O+

2000 ◽  
Vol 115 ◽  
pp. 295-302 ◽  
Author(s):  
S. Rose′n ◽  
A. Derkatch ◽  
J. Semaniak ◽  
A. Neau ◽  
A. Al-Khalili ◽  
...  
Keyword(s):  
Storage Ring ◽  
Dissociative Recombination ◽  
Molecular Ions

Dissociative recombination of electrons and molecular ions

1982 ◽  
Vol 136 (1) ◽  
pp. 25 ◽  
Author(s):  
Aleksandr V. Eletskii ◽  
Boris M. Smirnov
Keyword(s):  
Dissociative Recombination ◽  
Molecular Ions

scholarly journals Inferring thermospheric composition from ionogram profiles: a calibration with the TIMED spacecraft

2021 ◽  
Vol 39 (2) ◽  
pp. 309-319
Author(s):  
Christopher J. Scott ◽  
Shannon Jones ◽  
Luke A. Barnard
Keyword(s):  
Dissociative Recombination ◽  
Molecular Ions ◽  
Upper Atmosphere ◽  
Global Network ◽  
G Factor ◽  
Important Region ◽  
Term Change ◽  
Ion Production ◽  
Sensitive Function

Abstract. We present a method for augmenting spacecraft measurements of thermospheric composition with quantitative estimates of daytime thermospheric composition below 200 km, inferred from ionospheric data, for which there is a global network of ground-based stations. Measurements of thermospheric composition via ground-based instrumentation are challenging to make, and so details about this important region of the upper atmosphere are currently sparse. The visibility of the F1 peak in ionospheric soundings from ground-based instrumentation is a sensitive function of thermospheric composition. The ionospheric profile in the transition region between F1 and F2 peaks can be expressed by the “G” factor, a function of ion production rate and loss rates via ion–atom interchange reactions and dissociative recombination of molecular ions. This in turn can be expressed as the square of the ratio of ions lost via these processes. We compare estimates of the G factor obtained from ionograms recorded at Kwajalein (9∘ N, 167.2∘ E) for 25 times during which the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) spacecraft recorded approximately co-located measurements of the neutral thermosphere. We find a linear relationship between G and the molecular-to-atomic composition ratio, with a gradient of 2.55±0.40. Alternatively, using hmF1 values obtained by ionogram inversion, this gradient was found to be 4.75±0.4. Further, accounting for equal ionisation in molecular and atomic species yielded a gradient of 4.20±0.8. This relationship has potential for using ground-based ionospheric measurements to infer quantitative variations in the composition of the neutral thermosphere via a relatively simple model. This has applications in understanding long-term change and the efficacy of the upper atmosphere on satellite drag.

Astrochemical studies at the Cryogenic Storage Ring

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180412 ◽  
Author(s):  
H. Kreckel ◽  
O. Novotný ◽  
A. Wolf
Keyword(s):  
Storage Ring ◽  
Nuclear Physics ◽  
Molecular Ions ◽  
Rate Coefficients ◽  
Max Planck ◽  
Electron Recombination ◽  
Interstellar Molecule ◽  
Electron Cooler ◽  
Cryogenic Storage ◽  
Main Research

The new Cryogenic Storage Ring at the Max Planck Institute for Nuclear Physics (Heidelberg, Germany) has recently become operational. One of the main research areas foreseen for this unique facility is astrochemical studies with cold molecular ions. The spontaneous radiative cooling of the prototype interstellar molecule CH + to its lowest rotational states has been demonstrated by photodissociation spectroscopy, paving the way for experiments under true interstellar conditions. To this end, a low-energy electron cooler and a neutral atom beam set-up for merged beams studies have been constructed. These experiments have the potential to provide energy-resolved rate coefficients for fundamental astrochemical processes involving state-selected molecular ions. The main target reactions include some of the key processes of interstellar chemistry, such as the electron recombination of H 3 + , charge exchange between H 2 + and H, or the formation of CH + in collisions of triatomic hydrogen ions and C atoms. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

scholarly journals Quantum-state–selective electron recombination studies suggest enhanced abundance of primordial HeH+

Science ◽  
2019 ◽  
Vol 365 (6454) ◽  
pp. 676-679 ◽  
Author(s):  
Oldřich Novotný ◽  
Patrick Wilhelm ◽  
Daniel Paul ◽  
Ábel Kálosi ◽  
Sunny Saurabh ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Dissociative Recombination ◽  
Molecular Ions ◽  
Rate Coefficients ◽  
Specific Rate ◽  
Electron Recombination ◽  
Recombination Rates ◽  
Rotational States ◽  
Hydride Ion ◽  
Helium Hydride

The epoch of first star formation in the early Universe was dominated by simple atomic and molecular species consisting mainly of two elements: hydrogen and helium. Gaining insight into this constitutive era requires a thorough understanding of molecular reactivity under primordial conditions. We used a cryogenic ion storage ring combined with a merged electron beam to measure state-specific rate coefficients of dissociative recombination, a process by which electrons destroy molecular ions. We found a pronounced decrease of the electron recombination rates for the lowest rotational states of the helium hydride ion (HeH+), compared with previous measurements at room temperature. The reduced destruction of cold HeH+ translates into an enhanced abundance of this primordial molecule at redshifts of first star and galaxy formation.

Storage ring measurements of the dissociative recombination and excitation of the cyanogen ion CN+(X 1Σ+ and a 3Π, ν=0)

1999 ◽  
Vol 110 (2) ◽  
pp. 890-901 ◽  
Author(s):  
A. Le Padellec ◽  
J. B. A. Mitchell ◽  
A. Al-Khalili ◽  
H. Danared ◽  
A. Källberg ◽  
...  
Keyword(s):  
Storage Ring ◽  
Dissociative Recombination

scholarly journals Dissociative Recombination Measurements of Chloronium Ions (D2Cl+) Using an Ion Storage Ring

2018 ◽  
Vol 862 (2) ◽  
pp. 166 ◽  
Author(s):  
O. Novotný ◽  
H. Buhr ◽  
W. Geppert ◽  
M. Grieser ◽  
M. Hamberg ◽  
...  
Keyword(s):  
Storage Ring ◽  
Dissociative Recombination ◽  
Ion Storage
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