Temperature and energy dependences of ion–molecule reactions: Studies inspired by Diethard Böhme

2021 ◽  
Author(s):  
Albert A. Viggiano ◽  
Shaun G. Ard ◽  
Nicholas S. Shuman
Keyword(s):  
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>

Properties and Reactivity of First and Second Row Hydrides. IV. Interactions Between Hydrides and Their Radical Ions

1993 ◽  
Vol 58 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Rudolf Zahradník
Keyword(s):  
Radical Cations ◽  
Stabilization Energy ◽  
Hydrogen Atom Abstraction ◽  
Type Ii ◽  
Radical Ions ◽  
Reaction Products ◽  
Ion Molecule Reactions ◽  
Heats Of Reaction ◽  
Experimental Values ◽  
Easy Differentiation

The energies and heats of ion-molecule reactions have been calculated (MP4/6-31G**//6-31G** or better level) and compared with the experimental values obtained from the heats of formation. Two main types of reactions have been studied: (i) AHn + AHn+• ↔ AHn+1+ + AHn-1• (A = C to F and Si to Cl), (ii) AHn + BHm+• ↔ AHn+1+ + BHm-1• or AHn-1+• + BHm+1+ (A and B = C to F). In contrast to (i), processes of type (ii) permit easy differentiation between the proton transfer and hydrogen atom abstraction mechanisms. A third type of interaction involves reactions with radical anions (A = Li to F); comparison was made with analogous processes with radical cations. A brief comment is made about the influence of the level of computational sophistication on the energies and heats of reaction, as well as on the stabilization energy of a hydrogen bonded intermediate, a structure which is similar to that of the reaction products.

scholarly journals The chemistry of cool circumstellar envelopes

1987 ◽  
Vol 122 ◽  
pp. 551-552
Author(s):  
L.A.M. Nejad ◽  
T. J. Millar
Keyword(s):  
Kinetic Model ◽  
Chemical Kinetic ◽  
Time Dependent ◽  
Circumstellar Envelopes ◽  
Chemical Kinetic Model ◽  
Ion Molecule Reactions ◽  
Cool Stars

We have developed a time-dependent chemical kinetic model to describe the chemistry in the circumstellar envelopes of cool stars, with particular reference to IRC + 10216. Our detailed calculations show that ion-molecule reactions are important in the formation of many of the species observed in IRC + 10216.

Ion—Molecule Reactions in Methane and in Ethane

1964 ◽  
Vol 40 (1) ◽  
pp. 5-12 ◽  
Author(s):  
G. A. W. Derwish ◽  
A. Galli ◽  
A. Giardini‐Guidoni ◽  
G. G. Volpi
Keyword(s):  
Ion Molecule Reactions

Time-resolved ion cyclotron resonance

1978 ◽  
Vol 364 (1718) ◽  
pp. 367-381 ◽  
Keyword(s):  
Cyclotron Resonance ◽  
Low Energy ◽  
Interstellar Space ◽  
Ion Cyclotron Resonance ◽  
Absolute Rate ◽  
Time Resolved ◽  
Ion Molecule Reactions ◽  
Quadrupole Trap ◽  
Ion Cyclotron ◽  
Improved Technique

Ion cyclotron resonance (i. c. r.) is a technique for the study of ion-molecule reactions in the collisional range from thermal to several electron volts. The study of these reactions at low energy has been given impetus by the discovery of their importance in the ionosphere and in interstellar space. This communication identifies some possible weaknesses inherent in current i. c. r. work and suggests an improved technique with which it is possible to determine absolute rate constants more reliably. As an illustration of the technique a measurement of the rate constant for the reaction CH 4 + + CH 4 → k CH 5 + + CH 3 is presented. This value is k = 1.21 ± 0.09 × 10 -15 m 3 s -1 . A new i. c. r. cell design is discussed with which it is hoped to provide further improvement in reliability by the production of a homogeneous radiofrequency field within a true quadrupole trap.

Negative Ion‐Molecule Reactions

1959 ◽  
Vol 31 (5) ◽  
pp. 1426-1427 ◽  
Author(s):  
A. Henglein ◽  
G. A. Muccini
Keyword(s):  
Negative Ion ◽  
Ion Molecule Reactions
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