scholarly journals Cross Sections and Rate Coefficients for Rotational Excitation of HeH+ Molecule by Electron Impact

Atoms ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 49 ◽  
Author(s):  
Marjan Khamesian ◽  
Mehdi Ayouz ◽  
Jasmeet Singh ◽  
Viatcheslav Kokoouline
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Theoretical Approach ◽  
Analytical Formula ◽  
Rate Coefficients ◽  
Rotational Excitation ◽  
R Matrix ◽  
Wide Range ◽  
The Uk ◽  
Quantum Defect Theory

Cross sections for rotational excitation and de-excitation of the HeH+ ion by an electron impact are computed using a theoretical approach that combines the UK R-matrix code and the multi-channel quantum defect theory. The thermally-averaged rate coefficients derived from the obtained cross sections are fitted to an analytical formula valid for a wide range of temperatures.

scholarly journals Cross Sections and Rate Coefficients for Vibrational Excitation of H2O by Electron Impact

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 62
Author(s):  
Mehdi Ayouz ◽  
Alexandre Faure ◽  
Jonathan Tennyson ◽  
Maria Tudorovskaya ◽  
Viatcheslav Kokoouline
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
Normal Modes ◽  
Scattering Matrix ◽  
Rate Coefficients ◽  
Vibrational States ◽  
R Matrix ◽  
Frame Transformation ◽  
The Uk

Cross-sections and thermally averaged rate coefficients for vibration (de-)excitation of a water molecule by electron impact are computed; one and two quanta excitations are considered for all three normal modes. The calculations use a theoretical approach that combines the normal mode approximation for vibrational states of water, a vibrational frame transformation employed to evaluate the scattering matrix for vibrational transitions and the UK molecular R-matrix code. The interval of applicability of the rate coefficients is from 10 to 10,000 K. A comprehensive set of calculations is performed to assess uncertainty of the obtained data. The results should help in modelling non-LTE spectra of water in various astrophysical environments.

scholarly journals Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 67 ◽  
Author(s):  
Mehdi Ayouz ◽  
Viatcheslav Kokoouline
Keyword(s):  
Interstellar Medium ◽  
Electron Impact ◽  
Cross Sections ◽  
Theoretical Approach ◽  
Rate Coefficients ◽  
Tokamak Plasma ◽  
Vibration Excitation ◽  
Analytical Formulas

Cross sections and thermal rate coefficients for rotational and vibration excitation of the four stable isotopologues of the 4 HeH + ion by electron impact are presented. The data are calculated using a previously developed theoretical approach. The obtained rate coefficients are fitted to analytical formulas with the 10–10,000 K interval of applicability. These present results could be useful in tokamak plasma and astrophysical modeling and can help in the detection of these species in the interstellar medium.

scholarly journals Analytical Cross Section Approximation for Electron Impact Ionization of Alkali and Other Metals, Inert Gases and Hydrogen Atoms

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 90
Author(s):  
Rusudan I. Golyatina ◽  
Sergey A. Maiorov
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Alkali Metals ◽  
Impact Ionization ◽  
Analytical Formula ◽  
Theoretical Data ◽  
Electron Impact Ionization ◽  
Inert Gases ◽  
Hydrogen Atoms ◽  
Wide Range

The paper presents an analysis of data on the cross sections of electron impact ionization of atoms of alkali metals, hydrogen, noble gases, some transition metals and Al, Fe, Ni, W, Au, Hg, U. For the selected sets of experimental and theoretical data, an optimal analytical formula is found and approximation coefficients are calculated. The obtained semi-empirical formula reproduces the values of the ionization cross sections in a wide range of energies with an accuracy of the order of error of the available theoretical and experimental data.

scholarly journals Electron-impact double ionization of the carbon atom

2018 ◽  
Vol 620 ◽  
pp. A188 ◽  
Author(s):  
Valdas Jonauskas
Keyword(s):  
Carbon Atom ◽  
Electron Impact ◽  
Cross Sections ◽  
Double Ionization ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Ionization Cross ◽  
Ionization Cross Sections ◽  
Good Agreement

Electron-impact single- and double-ionization cross sections and Maxwellian rate coefficients are presented for the carbon atom. Scaling factors are introduced for the electron-impact excitation and ionization cross sections obtained in the distorted wave (DW) approximation. It is shown that the scaled DW cross sections provide good agreement with measurements for the single ionization of the C atom and C1+ ion. The direct double-ionization (DDI) process is studied using a multi-step approach. Ionization–ionization, excitation–ionization–ionization, and ionization–excitation–ionization branches are analyzed. It is demonstrated that the three-step processes contribute ≼40% of the total DDI cross sections for the case where one of the electrons takes all of the excess energy after the first ionization process.

scholarly journals Dissociative Recombination of CH+ Molecular Ion Induced by Very Low Energy Electrons

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 82 ◽  
Author(s):  
Zsolt J. Mezei ◽  
Michel D. Epée Epée ◽  
Ousmanou Motapon ◽  
Ioan F. Schneider
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Incident Energy ◽  
Dissociative Recombination ◽  
Boltzmann Distribution ◽  
Rate Coefficients ◽  
Rotational States ◽  
Low Energy Electrons ◽  
Quantum Defect Theory ◽  
Π State

We used the multichannel quantum defect theory to compute cross sections and rate coefficients for the dissociative recombination of CH + initially in its lowest vibrational level v i + = 0 with electrons of incident energy below 0.2 eV. We have focused on the contribution of the 2 2 Π state which is the main dissociative recombination route at low collision energies. The final cross section is obtained by averaging the relevant initial rotational states ( N i + = 0 , ⋯ , 10 ) with a 300 K Boltzmann distribution. The Maxwell isotropic rate coefficients for dissociative recombination are also calculated for different initial rotational states and for electronic temperatures up to a few hundred Kelvins. Our results are compared to storage-ring measurements.

Electron scattering from germanium tetrafluoride

RSC Advances ◽  
2014 ◽  
Vol 4 (109) ◽  
pp. 63817-63823 ◽  
Author(s):  
Biplab Goswami ◽  
Rahla Naghma ◽  
Bobby Antony
Keyword(s):  
Momentum Transfer ◽  
Electron Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Shape Resonance ◽  
Differential Cross Sections ◽  
Rotational Excitation ◽  
R Matrix ◽  
High Energies ◽  
Germanium Tetrafluoride

R-matrix and SCOP methods are used at low and high energies respectively to find e-GeF4 TCS. Electronic and rotational excitation, momentum transfer and elastic differential cross sections are also calculated. A shape resonance is observed at 5.7 eV.

Sign in / Sign up

Export Citation Format

Share Document