Ion-molecule reactions in uranium hexafluoride

1975 ◽  
Vol 28 (9) ◽  
pp. 1879 ◽  
Author(s):  
NA McAskill
Keyword(s):  
Kinetic Energy ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Uranium Hexafluoride ◽  
Ion Source ◽  
Rate Coefficients ◽  
Medium Pressure ◽  
Ion Molecule Reactions ◽  
Ion Kinetic Energy

The ion-molecule reactions of UF6 in the gas phase were studied in a mass spectrometer fitted with a medium-pressure ion source. The main reactions were the collision-stabilized formation of U2F11+ from UF5+, U2F10+ from UF4+ and U3F16+ from U2F10+. Rate coefficients for the reactions of UF5+ and UF4+ with UF6 and the distribution of their products were found to depend upon the ion kinetic energy.

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.

Ion-molecule reactions of methyl fluoride and methylene chloride

1970 ◽  
Vol 23 (11) ◽  
pp. 2301 ◽  
Author(s):  
NA McAskill
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Main Product ◽  
Methylene Chloride ◽  
Reaction Cross ◽  
Rate Coefficients ◽  
Ion Molecule Reactions ◽  
Reaction Cross Sections

The ion-molecule reactions of CH3F and CH2Cl2 were examined in the gas phase using a high-pressure mass spectrometer. The ionic products of CH3F were mainly CH2F+, C2H6F+, and CH4F+. In the CH2Cl2 system the main product was CHCl2+ together with smaller amounts of CH2Cl+, CH3Cl2+, and several condensation ions. The ionic reactivity of the two compounds was compared to that of other halomethanes. Rate coefficients and reaction cross sections for many primary reactant ions were measured as a function of the ion exit energy.

Ion–Molecule Reactions in Methyl Fluoride and Methyl Chloride

1971 ◽  
Vol 49 (13) ◽  
pp. 2217-2222 ◽  
Author(s):  
A. A. Herod ◽  
A. G. Harrison ◽  
N. A. McAskill
Keyword(s):  
Kinetic Energy ◽  
Methyl Chloride ◽  
Molecular Ions ◽  
Rate Coefficients ◽  
Minor Importance ◽  
Methyl Fluoride ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Ion Energies ◽  
Ion Kinetic Energy

The reactions of the molecular ion have been studied as a function of the ion kinetic energy for methyl fluoride and methyl chloride. The following reactions are observed[Formula: see text]For methyl fluoride (X = F) reactions c and d have kinetic energy thresholds and become significant at high ion energies. For CH3Cl (X = Cl) reaction a is not observed and reactions c and d are of only minor importance at high ion energies. Rate coefficients for the molecular ions and a number of fragment ions as well as rate coefficients for further reaction of CH4X+ are reported.

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>

The gas phase reactivity of the dimethylchloronium ion with alkylbenzenes

1981 ◽  
Vol 59 (15) ◽  
pp. 2412-2416 ◽  
Author(s):  
John A. Stone ◽  
Margaret S. Lin ◽  
Jeffrey Varah
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Aromatic Hydrocarbons ◽  
Relative Rate ◽  
Ion Source ◽  
Nucleophilic Displacement ◽  
Rate Of Reaction ◽  
Displacement Reactions ◽  
Bonded Complexes

The reactivity of the dimethylchloronium ion with a series of aromatic hydrocarbons has been studied in a high pressure mass spectrometer ion source using the technique of reactant ion monitoring. Benzene is unreactive but all others, from toluene to mesitylene, react by CH3+ transfer to yield σ-bonded complexes. The relative rate of reaction increases with increasing exothermicity in line with current theories of nucleophilic displacement reactions.

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.

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