Measurement of the rate coefficients for the bimolecular and termolecular ion–molecule reactions of Ar+2 with selected atomic and molecular species

1979 ◽  
Vol 71 (1) ◽  
pp. 184-191 ◽  
Author(s):  
C. B. Collins ◽  
F. W. Lee
Keyword(s):  
Molecular Species ◽  
Rate Coefficients ◽  
Ion Molecule Reactions

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

scholarly journals The Formation of Interstellar Molecules via Radiative Association Reactions

1980 ◽  
Vol 87 ◽  
pp. 323-324
Author(s):  
David Smith ◽  
Nigel G. Adams
Keyword(s):  
Rate Coefficients ◽  
Rate Data ◽  
Association Rate ◽  
Interstellar Molecules ◽  
Ion Molecule Reactions ◽  
Radiative Association ◽  
Temperature Dependences ◽  
Association Reaction

The radiative association rate coefficients and their temperature dependences have been estimated for several likely interstellar ion-molecule reactions from laboratory collisional association rate data. They include the CH3+ + H2 and CH3+ + H2O reactions, which we suggest lead to CH4 and CH3OH respectively, and the critical association reaction C+ + H2.

scholarly journals New Constraints on Diffuse Interstellar Cloud Models. The Model of the ζ Ophiuchi Cloud Revisited

1987 ◽  
Vol 120 ◽  
pp. 227-233
Author(s):  
Y. P. Viala ◽  
H. Abgrall ◽  
E. Roueff
Keyword(s):  
Molecular Species ◽  
Transfer Equation ◽  
Molecular Hydrogen ◽  
Reaction Rate ◽  
Radiative Transfer Equation ◽  
Interstellar Cloud ◽  
Rate Coefficients ◽  
Cloud Models ◽  
Parallel Geometry ◽  
Simple Molecules

Using most recent observational data as well as new experimental and theoretical determinations of various reaction rate coefficients, we present a model of the ζ θphiuchus cloud. the radiative transfer equation is solved in a plane parallel geometry taking into account absorptions by both the gas and by dust. A part certain atypical molecules (CH+, CN) and neutral iron, we are able to reproduce the observed column densities of neutral atoms, and molecular species, including the rotational populations of molecular Hydrogen with a two shell model. the concentrations of other simple molecules are predicted.

Termolecular ion–molecule reactions involving C3H5+

1970 ◽  
Vol 48 (22) ◽  
pp. 3549-3553 ◽  
Author(s):  
A. G. Harrison ◽  
A. A. Herod
Keyword(s):  
Kinetic Energy ◽  
Molecular Size ◽  
Order Rate Constant ◽  
Second Order ◽  
Rate Coefficients ◽  
Third Order ◽  
Order Rate ◽  
Ion Molecule Reactions ◽  
Similar Dependence ◽  
Ion Kinetic Energy

The reaction of C3H5+ with C2D4 to produce C5H5D4+ is shown to be second order in C2D4. The rate coefficients are in the range 10−24 to 10−25 cm6 molecule−2 s−1 but decrease markedly with increasing ion kinetic energy. This decrease reflects the effect of the ion kinetic energy on the lifetime of the initial collision complex. Small differences in rate coefficients are observed depending on the source of the C3H5+ ion but these are insufficient to distinguish between possibly different ionic structures. The reaction of C3H5+ with C2H3F forms C5H7+ in a reaction second order in C2H3F. The rate coefficients are also in the range 10−24 to 10−25 cm6 molecule−1 s−1 and show a similar dependence on ion kinetic energy. These high third order rate constants are compared with data for other termolecular reactions and are shown to be consistent with the effect of molecular size on the third order rate constant.

scholarly journals Bimolecular Reactions of Trapped Ions. VI. Ion–Molecule Reactions Involving CH5+ and C2H5+

1973 ◽  
Vol 51 (10) ◽  
pp. 1645-1654 ◽  
Author(s):  
A. S. Blair ◽  
A. G. Harrison
Keyword(s):  
Proton Transfer ◽  
Trapped Ions ◽  
Rate Coefficients ◽  
Polar Molecules ◽  
Large Role ◽  
Bimolecular Reactions ◽  
Trapped Ion ◽  
Ion Molecule Reactions ◽  
Dipole Interactions ◽  
Induced Dipole

The ion–molecule reactions in mixtures of methane with the polar molecules dimethyl-d6 ether, ethylene-d4 oxide, acetaldehyde-d4, acetone, and acetonitrile have been studied using the trapped-ion technique. The CH5+ and C2H5+ ions produced by ion–molecule reactions in methane react rapidly (predominantly by proton transfer) with the polar molecules; the rate coefficients range from 1.98 × 10−9 cm3 molecule−1 s−1 (C2H5+ + C2D4O) to 5.26 × 10−9 cm3 molecule−1 s−1 (CH5+ + (CH3)2CO). The rate coefficients are much larger than those predicted from ion – induced dipole interactions only indicating that ion–dipole interactions play a large role in the collision process.Rate coefficients for reaction of CH3+ and CH4+ with the polar molecules also have been measured. Most of these also are larger than predicted from ion – induced dipole interactions indicating in this case as well substantial effects due to ion–dipole interactions.

Ion-molecule reactions in methylene fluoride

1971 ◽  
Vol 24 (8) ◽  
pp. 1611 ◽  
Author(s):  
AG Harrison ◽  
NA McAskill
Keyword(s):  
Cross Sections ◽  
Ion Trap ◽  
Proton Transfer Reaction ◽  
Reaction Cross ◽  
Ion Source ◽  
Rate Coefficients ◽  
Main Reaction ◽  
Mass Spectrometers ◽  
Ion Molecule Reactions ◽  
Reaction Cross Sections

The ion-molecule reactions of CH2F2 in the gas phase were studied using two mass spectrometers, one fitted with a medium-pressure ion source and the other with an ion-trap source. The main reaction was the formation of CH2F+ from CHF2+. The molecular ion and its proton transfer reaction forming CH3F2+ were of lesser importance. The only condensation ion formed was C2H4F3+. Reaction cross sections and rate coefficients for a number of ions at exit energies of 0.2-3.3 eV were measured.

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

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