Metastable and collision-induced dissociation studies of unimolecular and bimolecular reactions in the C2H5O+, C2H7O+, and C2H8N+ systems: the role of methyl (CH3+) radiative association reactions in interstellar clouds

1986 ◽  
Vol 90 (1) ◽  
pp. 78-83 ◽  
Author(s):  
Martin F. Jarrold ◽  
Nicholas J. Kirchner ◽  
Shuying Liu ◽  
Michael T. Bowers
Keyword(s):  
Collision Induced Dissociation ◽  
Bimolecular Reactions ◽  
Interstellar Clouds ◽  
Radiative Association

Collision-induced dissociation dynamics in O2++Ne(Ar) collisions: The role of electronic excitation

2000 ◽  
Vol 113 (19) ◽  
pp. 8561-8566 ◽  
Author(s):  
Rainer A. Dressler ◽  
Yu-hui Chiu ◽  
Dale J. Levandier ◽  
C. Y. Ng
Keyword(s):  
Electronic Excitation ◽  
Collision Induced Dissociation ◽  
Dissociation Dynamics

scholarly journals Laboratory and Modeling Studies of Chemistry in Dense Molecular Clouds

1980 ◽  
Vol 87 ◽  
pp. 331-336
Author(s):  
W.T. Huntress ◽  
S. S. Prasad ◽  
G. F. Mitchell
Keyword(s):  
Chemical Equilibrium ◽  
Molecular Clouds ◽  
Evolutionary Model ◽  
Chemical Processes ◽  
Chemical Library ◽  
Interstellar Clouds ◽  
Organic Species ◽  
Radiative Association ◽  
Simple Chemical ◽  
Complex Organic

A chemical evolutionary model with a large number of species and a large chemical library is used to examine the principal chemical processes in interstellar clouds. Simple chemical equilibrium arguments show the potential for synthesis of very complex organic species by ion-molecule radiative association reactions.

COLLISIONS OF LONG-LIVED EXCITED IONS OF OXYGEN AND NITROGEN

1964 ◽  
Vol 42 (11) ◽  
pp. 2086-2101 ◽  
Author(s):  
William McGowan ◽  
Larkin Kerwin
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ion Beam ◽  
Collision Induced Dissociation ◽  
Ion Molecule Reactions ◽  
Collision Region ◽  
Mean Lifetime ◽  
New States ◽  
Product Ions

The role of some excited ions in laboratory ion–molecule reactions has been investigated, and their possible importance in the upper atmosphere considered. The mass spectrometer techniques of Aston banding and of comparing I.P. curves of parent and product ions have been applied to studies of collision-induced dissociation and charge exchange of oxygen and nitrogen in their parent gas. In every case studied, cross sections depended markedly upon the presence in the ion beam of ions in metastable or long-lived radiative states. In order that an ion reach the collision region, it had to have a mean lifetime greater than 3 μsec.The a 4Πu and b 4Σg excited states of O2+ were identified in the collision[Formula: see text]Higher states of O2+, which have not as yet been identified spectroscopically, were found in the collision[Formula: see text]The thresholds of these new states are 23.9, 27.9, 31.3, and 34.1 eV with an uncertainty ±0.2 eV. From the collision-induced dissociation of N2+, the A 2Πu and the [Formula: see text] states have been identified. Also, the reported transfer of the ν = 3 level of the B [Formula: see text] to the ν = 14 level of the A 2Πu was found.The cross section for 10/01 charged exchange of N2+ in N2 exhibited a marked decrease as excited-state ions diluted the beam. The 10/01 collisions of N+ in N2 and O+ in O2 exhibited an increase in cross section as metastables were added to the parent ion beam. The 10/20 reaction of O2+ in O2 was also observed to depend on excited O2+ ions.

scholarly journals Recent Advances in the studies of Reaction Rates relevant to Interstellar Chemistry

1987 ◽  
Vol 120 ◽  
pp. 1-18
Author(s):  
Nigel G. Adams ◽  
David Smith
Keyword(s):  
Laboratory Data ◽  
Dissociative Recombination ◽  
Reaction Rates ◽  
Rate Coefficients ◽  
Current Status ◽  
Laboratory Measurements ◽  
Interstellar Molecules ◽  
Interstellar Clouds ◽  
Radiative Association ◽  
Molecular Synthesis

The current status of laboratory measurements of the rate coefficients for ionic reactions involved in interstellar molecular synthesis is discussed and the experimental techniques used to acquire such data are briefly described. Examples are given of laboratory data which are being obtained at temperatures close to those of interstellar clouds. Particular attention is given to the results of recent theoretical and experimental work which show that the rate coefficients for the binary reactions of ions with polar molecules at low temperatures are much larger than previously assumed. It is shown how these new developments in experiment and theory are reconciling the differences between predicted and observed abundances for some interstellar molecules. Also briefly discussed are: - the phenomenon of isotope exchange in ion/neutral reactions which explains the apparent enrichment of heavy isotopes in some interstellar molecules, the role of atoms in molecular synthesis, some studies of ion/neutral reactions pertaining to shocked regions of interstellar clouds, ternary association reactions and the analogous radiative association reactions, and recent new laboratory measurements of dissociative recombination coefficients. Finally, some guidance is offered in the proper choice of critical kinetic data for use in interstellar chemical modelling and some further requirements and likely future developments are mentioned.

Sign in / Sign up

Export Citation Format

Share Document