scholarly journals Cross sections of electron collisions with noble gases atoms

2021 ◽  
pp. 11-16
Author(s):  
Rusudan Golyatina ◽  
Sergei Maiorov
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Noble Gas ◽  
Empirical Formulas ◽  
Electron Collisions ◽  
Wide Range ◽  
Analytical Formulas ◽  
The Cross ◽  
Approximation Coefficients ◽  
Ionization Cross Sections

Consideration is given to the analysis of data on the cross sections of elastic and inelastic col-lisions of electrons with noble gas atoms. The transport (diffusion) cross section, the excita-tion and ionization cross sections are studied. For the selected sets of experimental and theo-retical data, optimal analytical formulas are found and approximation coefficients are select-ed for them. The obtained semi-empirical formulas allow us to reproduce the cross section values in a wide range of collision energies from 0.001 to 10000 eV with an accuracy of sev-eral percent.

scholarly journals Analytical approximation of cross sections of collisions of electrons with atoms of inert gases

2021 ◽  
Vol 9 (4) ◽  
pp. 298-309
Author(s):  
Rusudan Golyatina ◽  
Sergei Maiorov
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Theoretical Data ◽  
Analytical Approximation ◽  
Inert Gases ◽  
Empirical Formulas ◽  
Wide Range ◽  
The Cross ◽  
Approximation Coefficients ◽  
Ionization Cross Sections

The paper presents an analysis of data on the cross sections of elastic and inelastic collisions of electrons with noble gas atoms. The transport (diffusion) cross sec-tion, the excitation and ionization cross sections are considered. For the selected sets of experimental and theoretical data, optimal analytical formulas are found and approximation coefficients are selected for them. The obtained semi-empirical formulas allow us to reproduce the cross section values in a wide range of colli-sion energies from 0.001 to 10000 eV with an accuracy of several percent.

scholarly journals Binary-Encounter Model for Direct Ionization of Molecules by Positron-Impact

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 99
Author(s):  
Małgorzata Franz ◽  
Katarzyna Wiciak-Pawłowska ◽  
Jan Franz
Keyword(s):  
Cross Sections ◽  
Positron Impact ◽  
Standard Quantum ◽  
Direct Ionization ◽  
Wide Range ◽  
Small Set ◽  
The Cross ◽  
Ionization Cross Sections ◽  
Binary Encounter ◽  
Good Agreement

We introduce two models for the computation of direct ionization cross sections by positron impact over a wide range of collision energies. The models are based on the binary-encounter-Bethe model and take into account an extension of the Wannier theory. The cross sections computed with these models show good agreement with experimental data. The extensions improve the agreement between theory and experiment for collision energies between the first ionization threshold and the peak of the cross section. The models are based on a small set of parameters, which can be computed with standard quantum chemistry program packages.

scholarly journals Electron scattering cross-sections for particle transport modeling in a weakly ionized air plasma

2021 ◽  
Vol 51 ◽  
pp. 96-111
Author(s):  
Vasily Sergeevich Zakharov ◽  
Mikhail Evgenievich Zhukovskiy ◽  
Sergey Vasilievich Zakharov ◽  
Mikhail Borisovich Markov
Keyword(s):  
Elastic Scattering ◽  
Cross Section ◽  
Electron Scattering ◽  
Cross Sections ◽  
Electron Interaction ◽  
Inelastic Electron ◽  
Neutral Atoms ◽  
Hartree Fock ◽  
Wide Range ◽  
The Cross

Data on processes of electron scattering on ions and neutral atoms are required in fundamental studies and in applied research in such fields as astro- and laser physics, low density plasma simulations, kinetic modeling etc. Experimental and computational data on elastic and inelastic electron scattering in a wide range of electron energies is available mostly for the electron interaction with neutral atoms, but are very limited for the scattering on ions, notably for elastic processes. In present work the calculational approaches for the cross-section computation of electron elastic and inelastic scattering on neutral atoms and ions are considered. The atomic and ion properties obtained in quantum-statistical Hartree-Fock-Slater model are used in the direct computation of electron elastic scattering and ionization cross-sections by a partial waves method, semiclassical and distorted-wave approximations. Calculated cross-sections for elastic scattering on nitrogen and oxygen atoms and ions, and electron ionisation cross-sections are compared with the available experimental data and widely used approximations and propose consistent results. Considering applicability of Hartree-Fock-Slater model in wide scope of temperatures and densities, such approach to the cross-section calculation can be used in a broad range of energies and ion charges.

The cross-section for ionization of O 5+ by electron impact

1963 ◽  
Vol 271 (1346) ◽  
pp. 379-386 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ionization Energy ◽  
Wave Method ◽  
Distorted Wave ◽  
Ionization Cross ◽  
The Cross ◽  
Ionization Cross Sections ◽  
Distorted Wave Method ◽  
Hydrogenic Ions

The calculation of ionization cross-sections is described. For O 5+ a Coulomb-Born-Oppenheimer method is used. Previous calculations for O 4+ with the distorted wave method are corrected and extended. The results are given in tables 1 to 4 and in figure 1. For O 4+ (ionization energy E i — 8·37 x 13·6 eV) the cross-section Q has its maximum at an energy of the incident electron E = 2·3 E i : Q max. = 2·74 x 10 -2 π a 2 0 = 2·42 x 10 -18 cm 2 . For O 5+ ( E i = 10·15 x 13·6 eV) the maximum is at E = 1·85 E i : Q max. = 0·97 x 10 -2 π a 2 0 = 0·86 x 10 -18 cm 2 . The corresponding reduced cross-sections Q red. = ( E i /13·6 eV ) 2 x Q /Kζπ a 2 0 ) are for O 4+ (ζ = 2): Q red. = 0·96, and for O 5+ (ζ = 1): Q red. = 1·00. The results are similar to those of Rudge & Burgess (1962) for hydrogenic ions.

TOTAL CROSS SECTIONS FOR IONIZATION BY ELECTRON IMPACT

1966 ◽  
Vol 44 (16) ◽  
pp. 1967-1973 ◽  
Author(s):  
A. G. Harrison ◽  
E. G. Jones ◽  
S. K. Gupta ◽  
G. P. Nagy
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Linear Correlation ◽  
Molecular Polarizability ◽  
Ionization Cross ◽  
Total Cross Sections ◽  
Atomic Ionization ◽  
Wide Range ◽  
The Cross ◽  
Ionization Cross Sections

Total cross sections for ionization by 75 V electrons have been measured for a wide range of molecules. On the whole the results are in agreement with the cross sections reported by Lampe etal. rather than those reported by Otvos and Stevenson. The results fit neither a single linear correlation with molecular polarizability nor a simple postulate of additivity of atomic ionization cross sections.

Analysis of the reaction Q-value effect using newly evaluated empirical formulas of (n,2n) cross-sections near 14.6MeV

2020 ◽  
Vol 29 (02) ◽  
pp. 2050005 ◽  
Author(s):  
M. Yiğit
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Measured Data ◽  
Q Value ◽  
Present Communication ◽  
Empirical Formulas ◽  
The Cross ◽  
Value Effect

Empirical formulas in determining the cross-sections play an important role at the energies of which there are no experimental data scattered about. The purpose of the present communication is to further improve the formulas of the cross-section of [Formula: see text] reactions at the energies near 14.6[Formula: see text]MeV. A systematics for the evaluation of these cross-sections is studied. We present the empirical formulas based on the statistical theory of nuclear reactions in connection with the compound nucleus. The new empirical formulas are found by using the experimental cross-sections as a function of the reaction [Formula: see text]-value. Thus, the new formulas provide the best description of the existing measured data compared with systematics suggested earlier by other authors.

scholarly journals Properties of individual contrails: a compilation of observations and some comparisons

2017 ◽  
Vol 17 (1) ◽  
pp. 403-438 ◽  
Author(s):  
Ulrich Schumann ◽  
Robert Baumann ◽  
Darrel Baumgardner ◽  
Sarah T. Bedka ◽  
David P. Duda ◽  
...  
Keyword(s):  
Water Content ◽  
Cross Section ◽  
Cross Sections ◽  
Threshold Temperature ◽  
Ambient Conditions ◽  
Ice Particles ◽  
Wide Range ◽  
Ice Water Content ◽  
The Cross ◽  
Ice Water

Abstract. Mean properties of individual contrails are characterized for a wide range of jet aircraft as a function of age during their life cycle from seconds to 11.5 h (7.4–18.7 km altitude, −88 to −31 °C ambient temperature), based on a compilation of about 230 previous in situ and remote sensing measurements. The airborne, satellite, and ground-based observations encompass exhaust contrails from jet aircraft from 1972 onwards, as well as a few older data for propeller aircraft. The contrails are characterized by mean ice particle sizes and concentrations, extinction, ice water content, optical depth, geometrical depth, and contrail width. Integral contrail properties include the cross-section area and total number of ice particles, total ice water content, and total extinction (area integral of extinction) per contrail length. When known, the contrail-causing aircraft and ambient conditions are characterized. The individual datasets are briefly described, including a few new analyses performed for this study, and compiled together to form a contrail library (COLI). The data are compared with results of the Contrail Cirrus Prediction (CoCiP) model. The observations confirm that the number of ice particles in contrails is controlled by the engine exhaust and the formation process in the jet phase, with some particle losses in the wake vortex phase, followed later by weak decreases with time. Contrail cross sections grow more quickly than expected from exhaust dilution. The cross-section-integrated extinction follows an algebraic approximation. The ratio of volume to effective mean radius decreases with time. The ice water content increases with increasing temperature, similar to non-contrail cirrus, while the equivalent relative humidity over ice saturation of the contrail ice mass increases at lower temperatures in the data. Several contrails were observed in warm air above the Schmidt–Appleman threshold temperature. The emission index of ice particles, i.e., the number of ice particles formed in the young contrail per burnt fuel mass, is estimated from the measured concentrations for estimated dilution; maximum values exceed 1015 kg−1. The dependence of the data on the observation methods is discussed. We find no obvious indication for significant contributions from spurious particles resulting from shattering of ice crystals on the microphysical probes.

scholarly journals Properties of individual contrails: A compilation of observations and some comparisons

2016 ◽  
Author(s):  
Ulrich Schumann ◽  
Robert Baumann ◽  
Darrel Baumgardner ◽  
Sarah T. Bedka ◽  
David P. Duda ◽  
...  
Keyword(s):  
Water Content ◽  
Cross Section ◽  
Cross Sections ◽  
Threshold Temperature ◽  
Ambient Conditions ◽  
Ice Particles ◽  
Wide Range ◽  
Ice Water Content ◽  
The Cross ◽  
Ice Water

Abstract. Mean properties of individual contrails are characterized for a wide range of jet aircraft as a function of age during their lifecycle from seconds to 11.5 hours (7.4 to 18.7 km altitude, −88 °C to −31 °C ambient temperature), based on a compilation of about 230 previous in-situ and remote sensing measurements. The airborne, satellite, and ground-based observations encompass exhaust contrails from jet aircraft since 1972, and a few older data for propeller aircraft. The contrails are characterized by mean ice particle sizes and concentrations, extinction, ice water content, optical depth, geometrical depth, and contrail width. Integral contrail properties include the cross-section area and total number of ice particles, total ice water content, and total extinction (area-integral of extinction) per contrail length. When known, the contrail-causing aircraft and ambient conditions are characterized. The individual datasets are briefly described, including a few new analyses performed for this study, and compiled together to form a "contrail library" (COLI). The data are compared with results of the Contrail Cirrus Prediction model CoCiP. The observations confirm that the number of ice particles in contrails is controlled by the engine exhaust and the formation process in the jet phase, with some particle losses in the wake vortex phase, followed later by weak decreases with time. Contrail cross-sections grow more quickly than expected from exhaust dilution. The cross-section integrated extinction follows an algebraic approximation. The ratio of volume to effective mean radius decreases with time. The ice water content increases with increasing temperature, similar to non-contrail cirrus, while the equivalent relative humidity over ice saturation of the contrail ice mass increases at lower temperatures in the data. Several contrails were observed in warm air above the Schmidt–Appleman threshold temperature. The “emission index” of ice particles, i.e. the number of ice particles formed in the young contrail per burnt fuel mass, is estimated from the measured concentrations for estimated dilution; maximum values exceed 1015 kg−1. The dependence of the data on the observation methods is discussed. We find no obvious indication for significant contributions from spurious particles resulting from shattering of ice crystals on the microphysical probes.

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

scholarly journals Total cross sections of eγ → $$ eX\overline{X} $$ processes with X = μ, γ, e via multiloop methods

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Roman N. Lee ◽  
Alexey A. Lyubyakin ◽  
Vyacheslav A. Stotsky
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Elliptic Integral ◽  
High Energy ◽  
Calculation Methods ◽  
Complete Elliptic Integral ◽  
Total Cross Sections ◽  
Multiloop Calculation ◽  
The Cross ◽  
Analytical Expressions

Abstract Using modern multiloop calculation methods, we derive the analytical expressions for the total cross sections of the processes e−γ →$$ {e}^{-}X\overline{X} $$ e − X X ¯ with X = μ, γ or e at arbitrary energies. For the first two processes our results are expressed via classical polylogarithms. The cross section of e−γ → e−e−e+ is represented as a one-fold integral of complete elliptic integral K and logarithms. Using our results, we calculate the threshold and high-energy asymptotics and compare them with available results.

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