Ion-molecule reactions of formic acid. II. Rearrangement reactions

1978 ◽  
Vol 31 (12) ◽  
pp. 2593 ◽  
Author(s):  
CG Freeman ◽  
PW Harland ◽  
MJ McEwan
Keyword(s):  
Charge Transfer ◽  
Formic Acid ◽  
General Equation ◽  
Rate Coefficients ◽  
Fragmentation Product ◽  
Ion Molecule Reactions ◽  
Positive Ions ◽  
Rearrangement Reactions

Rate coefficients for a number of rearrangement reactions of positive ions with HCOOH are reported. These reactions may be represented by the general equation �������������������������� Y+ + HCOOH → products Most reactant ions resulted in the fragmentation product HCO+ and five reactant ions, N+, O+, CN+, N2+ and CO+, were observed to have rate coefficients much greater than predicted by the ADO model. An explanation for the high rates observed for these reactant ions is proposed and involves dissociative charge transfer by a non-orbiting electron-jump mechanism.

Ion-molecule reactions of formic acid. I. Proton-transfer reactions

1978 ◽  
Vol 31 (10) ◽  
pp. 2157 ◽  
Author(s):  
CG Freeman ◽  
PW Harland ◽  
MJ McEwan
Keyword(s):  
Proton Transfer ◽  
Formic Acid ◽  
General Equation ◽  
Reasonable Agreement ◽  
Transfer Reactions ◽  
Rate Coefficients ◽  
Collision Rate ◽  
Dipole Orientation ◽  
Ion Molecule Reactions ◽  
Proton Transfer Reactions

Rate coefficients are reported for a number of proton-transfer reactions with formic acid. These reactions can be represented by the general equation �������������������������� XH++HCOOH → (HCOOH)H+ +X : (X = CH4, H2O, N2, CO, HCN, HCHO, CH3OH and H2S). Reasonable agreement was obtained between our observed results and predictions based on the average-dipole-orientation (ADO) model except that ADO theory may slightly underestimate the collision rate.

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.

Some ion-molecule reactions of hydrogen cyanide

1978 ◽  
Vol 31 (5) ◽  
pp. 963 ◽  
Author(s):  
CG Freeman ◽  
PW Harland ◽  
JP Liddy ◽  
MJ McEwan
Keyword(s):  
Gas Phase ◽  
Hydrogen Cyanide ◽  
Rate Coefficient ◽  
Rate Coefficients ◽  
Flowing Afterglow ◽  
Ion Molecule Reactions ◽  
Positive Ions

Rate coefficients for the reactions of several positive ions with HCN in the gas phase have been measured by the flowing afterglow technique. The reactions are all of the form ������������������������ X++HCN → products . where X+ and the corresponding rate coefficient, in units of cm3 molecule-1 s-1, are: X+ = HCN+ (k 9.8×10-10); C2N+ (k 3.1×10-10); CN+ (k 2.8×10-9 CH+ (k 3.2×10-9); H3O+ (k 4.5×10-9 and HCO+ (k 3.9×10-9).

A New AID for Interpolating and Assessing Collision Strengths and Rate Coefficients

1988 ◽  
Vol 102 ◽  
pp. 107-110
Author(s):  
A. Burgess ◽  
H.E. Mason ◽  
J.A. Tully
Keyword(s):  
Significant Loss ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Graphical Display ◽  
Practical Procedure ◽  
Positive Ions ◽  
Allowed Transition ◽  
Computational Errors ◽  
Existing Data

AbstractA new way of critically assessing and compacting data for electron impact excitation of positive ions is proposed. This method allows one (i) to detect possible printing and computational errors in the published tables, (ii) to interpolate and extrapolate the existing data as a function of energy or temperature, and (iii) to simplify considerably the storage and transfer of data without significant loss of information. Theoretical or experimental collision strengths Ω(E) are scaled and then plotted as functions of the colliding electron energy, the entire range of which is conveniently mapped onto the interval (0,1). For a given transition the scaled Ω can be accurately represented - usually to within a fraction of a percent - by a 5 point least squares spline. Further details are given in (2). Similar techniques enable thermally averaged collision strengths upsilon (T) to be obtained at arbitrary temperatures in the interval 0 < T < ∞. Application of the method is possible by means of an interactive program with graphical display (2). To illustrate this practical procedure we use the program to treat Ω for the optically allowed transition 2s → 2p in ArXVI.

Photoinduced Charge Transfer Dynamics in Carotenoid-Porphyrin-C60 Triad via the Linearized Semiclassical Nonequilibrium Fermi's Golden Rule

2020 ◽  
Author(s):  
Zhengqing Tong ◽  
Margaret S. Cheung ◽  
Barry D. Dunietz ◽  
Eitan Geva ◽  
Xiang Sun
Keyword(s):  
Charge Transfer ◽  
Golden Rule ◽  
Time Dependent ◽  
Rate Coefficients ◽  
Initial State ◽  
Photoinduced Charge Transfer ◽  
Transfer Rates ◽  
Fermi's Golden Rule ◽  
Photoinduced Charge ◽  
Fermi’S Golden Rule

The nonequilibrium Fermi’s golden rule (NE-FGR) describes the time-dependent rate coefficient for electronic transitions, when the nuclear degrees of freedom start out in a <i>nonequilibrium</i> state. In this letter, the linearized semiclassical (LSC) approximation of the NE-FGR is used to calculate the photoinduced charge transfer rates in the carotenoid-porphyrin-C<sub>60</sub> molecular triad dissolved in explicit tetrahydrofuran. The initial nonequilibrium state corresponds to impulsive photoexcitation from the equilibrated ground-state to the ππ* state, and the porphyrin-to-C<sub>60</sub> and the carotenoid-to-C<sub>60</sub> charge transfer rates are calculated. Our results show that accounting for the nonequilibrium nature of the initial state significantly enhances the transition rate of the porphyrin-to-C<sub>60</sub> CT process. We also derive the instantaneous Marcus theory (IMT) from LSC NE-FGR, which casts the CT rate coefficients in terms of a Marcus-like expression, with explicitly time-dependent reorganization energy and reaction free energy. IMT is found to reproduce the CT rates in the system under consideration remarkably well.

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>

scholarly journals The Formation of Interstellar Molecules via Radiative Association Reactions

1980 ◽  
Vol 87 ◽  
pp. 323-324
Author(s):  
David Smith ◽  
Nigel G. Adams
Keyword(s):  
Rate Coefficients ◽  
Rate Data ◽  
Association Rate ◽  
Interstellar Molecules ◽  
Ion Molecule Reactions ◽  
Radiative Association ◽  
Temperature Dependences ◽  
Association Reaction

The radiative association rate coefficients and their temperature dependences have been estimated for several likely interstellar ion-molecule reactions from laboratory collisional association rate data. They include the CH3+ + H2 and CH3+ + H2O reactions, which we suggest lead to CH4 and CH3OH respectively, and the critical association reaction C+ + H2.

scholarly journals Excitation and charge transfer in low-energy hydrogen atom collisions with neutral carbon and nitrogen

2019 ◽  
Vol 625 ◽  
pp. A78 ◽  
Author(s):  
A. M. Amarsi ◽  
P. S. Barklem
Keyword(s):  
Charge Transfer ◽  
Neutral Hydrogen ◽  
Stellar Atmospheres ◽  
Low Energy ◽  
Rate Coefficients ◽  
Collision Dynamics ◽  
Hydrogen Atoms ◽  
Stellar Spectra ◽  
Zero Rate ◽  
Excitation Processes

Low-energy inelastic collisions with neutral hydrogen atoms are important processes in stellar atmospheres, and a persistent source of uncertainty in non-LTE modelling of stellar spectra. We have calculated and studied excitation and charge transfer of C I and of N I due to such collisions. We used a previously presented method that is based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions for the adiabatic potential energies, combined with the multichannel Landau-Zener model for the collision dynamics. We find that charge transfer processes typically lead to much larger rate coefficients than excitation processes do, consistent with studies of other atomic species. Two-electron processes were considered and lead to non-zero rate coefficients that can potentially impact statistical equilibrium calculations. However, they were included in the model in an approximate way, via an estimate for the two-electron coupling that was presented earlier in the literature: the validity of these data should be checked in a future work.

scholarly journals State-Diagnosed Ion-Neutral Collisions leading to Charge Transfer

1987 ◽  
Vol 120 ◽  
pp. 27-28
Author(s):  
D. Mathur ◽  
C. Badrinathan ◽  
F. A. Rajgara ◽  
U. T. Raheja
Keyword(s):  
Charge Transfer ◽  
High Resolution ◽  
Electronic States ◽  
Translational Energy ◽  
Astrophysical Plasmas ◽  
Positive Ions ◽  
Multiply Charged ◽  
Single Electron Capture ◽  
Gain Loss ◽  
Inelastic Processes

A significant reservoir of potential energy in hot astrophysical plasmas exists in multiply charged positive ions. Inelastic collisional processes involving such ions govern the ionization and energy balance in such plasmas. Although inelastic processes such as, charge transfer, have been widely investigated, there remains a paucity of knowledge about charge changing processes where both reactions and products are state-diagnosed. We have applied high-resolution translational energy gain/loss spectroscopy to investigate state-diagnosed collisions between Kr2+ and H2 leading to single electron capture into specific electronic states of Kr+ at collision energies in the range 1–6 keV.

Radiative charge transfer and radiative association of helium ions with neon atoms

1984 ◽  
Vol 62 (12) ◽  
pp. 1622-1628 ◽  
Author(s):  
D. L. Cooper ◽  
K. Kirby ◽  
A. Dalgarno
Keyword(s):  
Charge Transfer ◽  
Dipole Moments ◽  
Rate Coefficients ◽  
Spin Orbit ◽  
Helium Ions ◽  
Transition Dipole ◽  
Radiative Association ◽  
Transition Dipole Moments ◽  
Spin Orbit Interactions ◽  
Comparison With Experimental Data

Ab initio calculations are carried out for the dipole moments of the X2Σ+, A2Π, and B2Σ+ states of HeNe+, and the transition dipole moments connecting them. The effects of spin-orbit interactions are explored briefly. The transition dipole moments are used in a calculation of the rate coefficients of radiative charge transfer and radiative association of He+ ions in neon and the associated spectra are obtained. Comparison with experimental data provides support for the conclusion that the radiation detected was emitted in the course of the collisions of He+ with Ne. Some quantitative discrepancies remain which may arise from intensity stealing by the A22Π1/2 state from the X2Σ+ state.

Sign in / Sign up

Export Citation Format

Share Document