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.

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 ketones

1965 ◽  
Vol 18 (8) ◽  
pp. 1153 ◽  
Author(s):  
Souza BC de ◽  
JH Green
Keyword(s):  
Cross Sections ◽  
Hydrogen Abstraction ◽  
Reaction Cross ◽  
Ion Source ◽  
Principal Mode ◽  
Ion Molecule Reactions ◽  
Elevated Pressures ◽  
Secondary Ions ◽  
Ion Proton ◽  
Approximate Rate

Reactions with gaseous ketones in the ion source of a mass spectrometer at elevated pressures have been studied. Reaction cross sections and approximate rate constants are reported for reactions leading to ions of mass M + 1, where M is the mass of the parent ion. Proton transfer rather than hydrogen abstraction seems to be the principal mode of reaction in the formation of these secondary ions.

CONCURRENT ION–MOLECULE REACTIONS LEADING TO THE SAME PRODUCTION

1962 ◽  
Vol 40 (10) ◽  
pp. 1986-1996 ◽  
Author(s):  
A. G. Harrison ◽  
J. M. S. Tait
Keyword(s):  
High Pressure ◽  
Mass Spectrum ◽  
Cross Sections ◽  
Reaction Cross ◽  
Ion Molecule Reactions ◽  
Secondary Ions ◽  
Primary Ions ◽  
Reaction Cross Sections

Seven of the major secondary ions in the high-pressure mass spectrum of cyclopropane have been studied. A method has been developed for studying concurrent ion–molecule reactions and it has been shown that four of the secondary ions are the products of more than one reaction. Cross sections for the separate reactions are reported. The appearance potentials of the major primary ions in the mass spectrum of cyclopropane have been 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>

Formation of α clusters in dilute neutron-rich matter

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 260-264 ◽  
Author(s):  
Junki Tanaka ◽  
Zaihong Yang ◽  
Stefan Typel ◽  
Satoshi Adachi ◽  
Shiwei Bai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cluster Formation ◽  
Reaction Cross ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Heavy Nuclei ◽  
Α Decay ◽  
Neutron Skin Thickness ◽  
Reaction Cross Sections ◽  
Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

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