Chemistry of Positive Ions. II. Ion—Molecule Reactions in Radiolysis of n‐Hexane at Low Temperatures

1962 ◽  
Vol 37 (10) ◽  
pp. 2496-2497 ◽  
Author(s):  
Larry Kevan ◽  
W. F. Libby
Keyword(s):  
Low Temperatures ◽  
Ion Molecule Reactions ◽  
Positive Ions

Molecular-physics aspects of cold chemistry

2019 ◽  
pp. 82-141
Author(s):  
FrÉdÉric Merkt
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Molecular Physics ◽  
Exothermic Reactions ◽  
Langevin Model ◽  
Ion Molecule Reactions ◽  
Radiative Association ◽  
Association Reaction ◽  
Oppenheimer Approximation ◽  
General Aspects

Molecular-physics aspects of cold chemistry are introduced with the example of few-electron molecules. After a brief overview of general aspects of molecular physics, the solution of the molecular Schrödinger equation is presented based on the Born-Oppenheimer approximation and the subsequent evaluation of adiabatic, nonadiabatic, relativistic and radiative (QED) corrections. Low-temperature chemical phenomena are introduced with the example of ion-molecule reactions, using the classical Langevin model for barrier-free exothermic reactions as reference. Then, methods to generate cold few-electron molecules by supersonic-beam-deceleration methods such as Stark, Zeeman, and Rydberg-Stark decelerations are presented. Two astrophysically important reactions, the reaction between H2 and H2+ forming H3+ and H, a very fast reaction following Langevin-capture going over to quantum-Langevin capture at low temperature, and the radiative association reaction H+ + H forming H2+, a very slow reaction in which quantum effects (shape resonances) become important at low temperatures, are used to illustrate the concepts introduced.

Radiolysis of ethyl iodide and carbon tetrachloride mixtures at 77°K

1968 ◽  
Vol 46 (10) ◽  
pp. 1625-1632 ◽  
Author(s):  
R. M. Leblanc ◽  
F. C. Thyrion ◽  
J. A. Herman
Keyword(s):  
Electron Spin Resonance ◽  
Charge Transfer ◽  
Carbon Tetrachloride ◽  
Electron Spin ◽  
Ethyl Iodide ◽  
Ion Molecule Reactions ◽  
Positive Ions ◽  
Spin Resonance ◽  
Γ Rays ◽  
The Difference

The radical yields of C2H5• and CCl3• observed by electron spin resonance of CCl4 + C2H5I mixtures irradiated by γ rays at 77°K are compared with yields of HCl, I2, and HI measured after thawing. The dissociative capture of thermalized electrons by CCl4 is extremely effective and accounts for most of the observed radicals. The difference between yields of HCl and CCl3• results from charge transfer from C2H5I+ to CCl3•. The formation of iodine proceeds both from neutralization processes of Cl− ions with positive ions formed from C2H5I, and from ion–molecule reactions.

scholarly journals Cover Picture: New Method to Study Ion-Molecule Reactions at Low Temperatures and Application to the H2++H2→H3++H Reaction (ChemPhysChem 22/2016)

ChemPhysChem ◽  
2016 ◽  
Vol 17 (22) ◽  
pp. 3578-3578 ◽  
Author(s):  
Pitt Allmendinger ◽  
Johannes Deiglmayr ◽  
Otto Schullian ◽  
Katharina Höveler ◽  
Josef A. Agner ◽  
...  
Keyword(s):  
Low Temperatures ◽  
New Method ◽  
Ion Molecule Reactions

scholarly journals New Method to Study Ion-Molecule Reactions at Low Temperatures and Application to the H2++H2→H3++H Reaction

ChemPhysChem ◽  
2016 ◽  
Vol 17 (22) ◽  
pp. 3580-3580
Author(s):  
Pitt Allmendinger ◽  
Johannes Deiglmayr ◽  
Otto Schullian ◽  
Katharina Höveler ◽  
Josef A. Agner ◽  
...  
Keyword(s):  
Low Temperatures ◽  
New Method ◽  
Ion Molecule Reactions

scholarly journals A mass-selective ion transfer line coupled with a uniform supersonic flow for studying ion–molecule reactions at low temperatures

2019 ◽  
Vol 150 (16) ◽  
pp. 164201 ◽  
Author(s):  
B. Joalland ◽  
N. Jamal-Eddine ◽  
D. Papanastasiou ◽  
A. Lekkas ◽  
S. Carles ◽  
...  
Keyword(s):  
Supersonic Flow ◽  
Low Temperatures ◽  
Ion Transfer ◽  
Ion Molecule Reactions ◽  
Transfer Line

Laboratory studies of isotope exchange in ion-neutral reactions: interstellar implications

1981 ◽  
Vol 303 (1480) ◽  
pp. 535-542 ◽  
Keyword(s):  
Low Temperatures ◽  
Isotope Exchange ◽  
Laboratory Data ◽  
Isotopic Ratios ◽  
Laboratory Studies ◽  
Terrestrial Environment ◽  
Interstellar Clouds ◽  
Ion Molecule Reactions ◽  
Significant Process ◽  
Molecule Interactions

The rare stable isotopes of several elements (e.g. D, 13 C and 15 N) have been detected in several interstellar molecules, and their abundance relative to the more common isotope is often enhanced above that in the solar-terrestrial environment. Important questions to answer are to what extent the isotopic ratios in the molecules are representative of those in the cloud matter as a whole, and whether fractionation of the heavier isotope into the molecules via ion—molecule interactions is a significant process. A laboratory study of isotope exchange in ion-molecule reactions has therefore been carried out, the results of which indicate that fractionation of heavy isotopes can occur very efficiently at low temperatures. Consideration is given in this paper to reactions in which H-D, 12 C - 13 C, 14 N - 15 N and 16 O - 18 O exchange occurs, and it is shown how better estimates of the electron density and the temperature in interstellar clouds have been obtained from these laboratory data.

scholarly journals The Drift Velocity of Potassium Ions in Hydrogen at 293°K

1967 ◽  
Vol 20 (4) ◽  
pp. 471 ◽  
Author(s):  
MT Elford
Keyword(s):  
Drift Velocity ◽  
Large Body ◽  
Drift Chamber ◽  
Molecular Ions ◽  
Ion Source ◽  
Potassium Ions ◽  
Velocity Measurements ◽  
Ion Molecule Reactions ◽  
Positive Ions ◽  
Design Experiments

Although there exists a large body of data for the drift velocity of positive ions in gases (Loeb 1955; McDaniel 1964), some of the data are conflicting or ambiguous due to uncertainty concerning the identity of the ion being studied (Dalgarno, McDowell, and Williams 1958; Davies et al. 1966). This ambiguity isparticularly serious in the case of atomic or molecular ions moving in the parent gas, since ion-molecule reactions may occur in the ion source or within the drift chamber. The necessity for simultaneous drift velocity measurements and ion identification has led a number of workers (e.g. Edelson and McAffee 1964; Keller, Martin, and McDaniel 1965; Madson, Oskam, and Chanin 1965; Saporoschenko 1965) to design experiments in which such identification is possible. In these experiments the gas pressure in the drift chamber is of the order of a few torr while that in the mass spectrometer is usually less than 10-5 torr.

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