Cross sections for symmetric charge transfer and proton transfer reactions of internal energy selected NH3+ (v)

1981 ◽  
Vol 75 (9) ◽  
pp. 4477-4484 ◽  
Author(s):  
Tomas Baer ◽  
P. Terrence Murray
Keyword(s):  
Charge Transfer ◽  
Proton Transfer ◽  
Internal Energy ◽  
Cross Sections ◽  
Transfer Reactions ◽  
Proton Transfer Reactions

Mass Spectrometric Observation of Electron and Proton Transfer Reactions between Positive Ions and Neutral Molecules

1962 ◽  
Vol 17 (6) ◽  
pp. 452-460 ◽  
Author(s):  
A. Henglein ◽  
G. A. Muccini
Keyword(s):  
Charge Transfer ◽  
Proton Transfer ◽  
Cross Sections ◽  
Low Voltage ◽  
Molecular Size ◽  
Ion Source ◽  
Mass Spectrometric ◽  
Transfer Reactions ◽  
Fragment Ions ◽  
Proton Transfer Reactions

The method of CERMAK and HERMAN has been applied to mass spectrometric studies of symmetrical electron and proton transfer processes. The characteristics of the ion source used have been investigated both experimentally and theoretically. A new type of ionization efficiency curve is obtained if the current o secondary ion is plotted as a function of the voltage between ionization chamber and electron trap at constant low voltage between the filament and the chamber. Essentially complete discrimination of primary ions has been achieved.Electron transfer occurs with rather low cross section in methane but increases with molecular size and with increasing unsaturation. Large cross sections were observed in sulfur and iodine containing compounds. Double charge transfer reactions such asNO++ + NO → NO + NO++, Xe++ + Xe → Xe + Xe++have also been observed. Proton transfer reactions have been observed in several simple molecules. Some experimental results are presented which indicate that proton transfer may occur via a complex (at low kinetic energies) or as a stripping process (at higher energies).Fragment ions have also been observed in the secondary mass spectra of several compounds. While part of these may result from the scattering of primary fragment ions, in some cases additional processes have to be postulated such as hydride ion transfer and dissociative charge transfer from vibrationally excited ions.

Velocity Map Imaging Study of Charge-Transfer and Proton-Transfer Reactions of CH3 Radicals with H3+

2015 ◽  
Vol 6 (9) ◽  
pp. 1684-1689 ◽  
Author(s):  
Linsen Pei ◽  
Eduardo Carrascosa ◽  
Nan Yang ◽  
Stefano Falcinelli ◽  
James M. Farrar
Keyword(s):  
Charge Transfer ◽  
Proton Transfer ◽  
Imaging Study ◽  
Transfer Reactions ◽  
Velocity Map Imaging ◽  
Proton Transfer Reactions

Mass Spectrometric Observation of Electron and Proton Transfer Reactions between Positive Ions and Neutral Molecules. Part II

1963 ◽  
Vol 18 (6) ◽  
pp. 753-761
Author(s):  
A. Henglein ◽  
G. A. Muccini
Keyword(s):  
Proton Transfer ◽  
Isotope Effect ◽  
Cross Sections ◽  
Ion Source ◽  
Transfer Reactions ◽  
Secondary Ions ◽  
Slow Ions ◽  
Proton Transfer Reactions ◽  
Order Of Magnitude ◽  
Doubly Charged

The method of Cermak and Herman has been applied to studies of unsymmetrical charge and proton transfer reactions. If the charge is transferred between atoms low cross sections are observed since part of the kinetic energy of the reacting system has to be converted into internal energy of the reactants. Large cross sections, however, have been found for the charge transfer between polyatomic species where apparently no resonance restriction exists. In several instances the unsymmetrical transfer B++A ➝ B+A+ has a higher rate than either of the processes B++B or A++A. If the ionization potential of B is lower than that of A the cross sections are in general low. In certain cases exceptionally large cross sections are observed and can be explained by the excess energy of a long lived excited state of the donor B+. Dissociations following the transfer of one charge from a doubly charged ion to a neutral molecule such asKr+++H2O ➝ (Kr+)*+ (H2O+)* ➝ OH++H ,NO+++NO ➝ (NO+)*+(NO+)* ➝ N++Ohave also been observed. The results indicate that the doubly charged ion generally captures the electron into a high lying orbital.Protonated cyclopropane is shown to be readily formed in ionized cyclopropane. In mixtures of water and methane, proton transfer has been observed in both directions. A large isotope effect on the secondary ion currents resulting from the transfer of a deuteron or a proton has been found in several simple systems. This isotope effect appears only if the secondary ions are observed in the Cermak—Herman method and is not found in the conventional operating of the ion source where reactions of slow ions predominate. This information provides some insite into the mechanistic details of the proton transfer since little isotope effect is expected if the reaction occurs via an inelastic collision complex while an isotope effect of the order of magnitude observed here is predicted by a stripping model.

Sign in / Sign up

Export Citation Format

Share Document