Many-Electron Correlations in the Photoionization of a Nitrogen Atom

1974 ◽  
Vol 52 (4) ◽  
pp. 349-354 ◽  
Author(s):  
N. A. Cherepkov ◽  
L. V. Chernysheva ◽  
V. Radojević ◽  
I. Pavlin
Keyword(s):  
Nitrogen Atom ◽  
Cross Section ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Electron Correlations ◽  
Sum Rule ◽  
Hartree Fock ◽  
The Cross ◽  
Good Agreement

Photoionization cross sections for the outer shell of the nitrogen atom ground state are calculated in the single-particle Hartree–Fock approximation and, in order to take into account many-electron correlations, also in the Random Phase Approximation with Exchange (RPAE). To be able to apply the RPAE, its modification for the half-filled shell atom, such as nitrogen atom, is presented. Calculation of length and velocity forms of the cross section in both approximations are compared with the available experimental data, and a good agreement is obtained. It has been found that in the RPAE the influence of many-electron correlations in a nitrogen atom is not great, but it is very important since, in contrast to the Hartree–Fock approximation, it results in the validity of the sum rule and the coincidence of the length and velocity forms of the cross sections, in agreement with the requirement of the general theory. The angular distribution of photoelectrons is also calculated in the RPAE, which has not been measured so far.

COMPTON SCATTERING CROSS SECTIONS FOR HEAVY ATOMS WITH ACCOUNT OF MANY-ELECTRON CORRELATIONS

2002 ◽  
Vol 09 (02) ◽  
pp. 1155-1160 ◽  
Author(s):  
M. YA. AMUSIA ◽  
L. V. CHERNYSHEVA ◽  
Z. FELFLI ◽  
A. Z. MSEZANE
Keyword(s):  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation ◽  
Electron Correlations ◽  
Hartree Fock ◽  
Heavy Atoms ◽  
The One ◽  
Scattering Cross Sections ◽  
Electron Effects

Compton ionization of krypton and xenon outer and intermediate subshells is investigated. Results are presented covering the energy transferred to the atoms from their ionization thresholds up to 30 Ry and momentum transferred up to 4 a.u. Calculations are performed in the one-electron Hartree–Fock approximation and with many-electron effects taken into account in the random phase approximation with exchange. It is demonstrated that many-electron correlations play an important role not only in dipole but also in monopole and quadrupole transitions, significantly modifying the cross sections as well as leading to new maxima and minima.

A new empirical formula for cross-sections of (n,nα) reactions

2020 ◽  
Vol 29 (08) ◽  
pp. 2050062
Author(s):  
Mustafa Yiğit
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Empirical Formula ◽  
Nuclear Reactions ◽  
Measured Cross Section ◽  
Future Studies ◽  
Present Formalism ◽  
The Cross ◽  
Neutron Cross Sections ◽  
Good Agreement

Studies on the cross-sections of (n,n[Formula: see text]) reactions which are energetically possible, about 14 MeV neutrons are quite scarce. In this paper, the cross-sections of (n,n[Formula: see text] nuclear reactions at [Formula: see text]14–15 MeV are analyzed by using a new empirical formula based on the statistical theory. We show that neutron cross-sections are closely related to the [Formula: see text]-value of nuclear reaction, in particular for (n,n[Formula: see text]) channels. Results obtained with this empirical formula show good agreement with the available measured cross-section values. We hope that the estimations on the cross-sections using the present formalism may be helpful in future studies in this field.

scholarly journals Cross Section Ionization By Electron Impact Of Helium Like Ions

2021 ◽  
Author(s):  
Manel Hariz Belgacem ◽  
Elhabib Guedda ◽  
Haikel Jelassi
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
The Cross ◽  
State 1 ◽  
Unstable States ◽  
Good Agreement

<sub></sub> In this paper we present our calculation of the cross section ionization by electron impact of C V, N VI and O VII. Using the Flexible Atomic Code (FAC), we obtain the cross sections for the ionization of these ions from the ground state 1<sup>1</sup>S, and from the unstable states 2<sup>1</sup>S and 2<sup>3</sup>S. Our results are in good agreement with those based on the Coulomb Born (CB) approximation and the available measurements.

scholarly journals 14.8 MeV Neutron Activation Cross Section Measurements for Ge Isotopes

2009 ◽  
Vol 1 (2) ◽  
pp. 173-181 ◽  
Author(s):  
M. M. Haque ◽  
M. T. Islam ◽  
M. A. Hafiz ◽  
R. U. Miah ◽  
M. S. Uddin
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Gamma Ray ◽  
Reaction Cross ◽  
Activation Cross Section ◽  
Section Data ◽  
Gamma Ray Spectroscopy ◽  
24Na Reaction ◽  
The Cross ◽  
Good Agreement

The cross sections of Ge isotopes were measured with the activation method at 14.8 MeV neutron energy. The quasi-monoenergetic neutron beams were produced via the 3H(d,n)4He reaction at the 150 kV J-25 neutron generator of INST, AERE. The characteristics γ-lines of the product nuclei were measured with a closed end coaxial 17.5 cm2 high purity germanium (HPGe) detector gamma ray spectroscopy. The cross sections were determined with reference to the known 27Al(n,α)24Na reaction. Cross section data are presented for 72Ge(n,p)72Ga, 74Ge(n,α)71mZn and 76Ge(n,2n)75m+gGe reactions. The cross section values obtained for the above reactions were 24.78±1.75 mb, 1.69±0.11 mb and 860±50 mb, respectively. The results obtained were compared with the values reported in literature as well as theoretical calculation performed by the statistical code SINCROS-II. The experimental data were found fairly in good agreement with the calculated and literature data.  Keywords: Activation cross section; Neutron induced reaction; Gamma-ray spectroscopy; 14.8 MeV. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i2.1532  

scholarly journals γ-ray strength function for astrophysical applications in the IAEA-CRP

2020 ◽  
Vol 239 ◽  
pp. 07005
Author(s):  
Hiroaki Utsunomiya ◽  
Stephane Goriely ◽  
Therese Renstrøm ◽  
Gry M. Tveten ◽  
Takashi Ari-izumi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Random Phase Approximation ◽  
Function Method ◽  
Strength Function ◽  
Random Phase ◽  
Phase Approximation ◽  
Quasiparticle Random Phase Approximation ◽  
Hartree Fock ◽  
Γ Ray

The γ-ray strength function (γSF) is a nuclear quantity that governs photoabsorption in (γ, n) and photoemission in (n, γ) reactions. Within the framework of the γ-ray strength function method, we use (γ, n) cross sections as experimental constraints on the γSF from the Hartree-Fock-Bogolyubov plus quasiparticle-random phase approximation based on the Gogny D1M interaction for E1 and M1 components. The experimentally constrained γSF is further supplemented with the zero-limit M1 and E1 strengths to construct the downward γSF with which (n, γ) cross sections are calculated. We investigate (n, γ) cross sections in the context of astrophysical applications over the nickel and barium isotopic chains along the s-process path.

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.

Discrepancy of in-medium nucleon–nucleon cross-section in different T-matrix representations

2014 ◽  
Vol 23 (04) ◽  
pp. 1450023 ◽  
Author(s):  
Yong-Zhong Xing ◽  
Xing-Wen Zhao
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nucleon Nucleon ◽  
Matrix Representations ◽  
Proton Proton ◽  
Hartree Fock ◽  
Wave States ◽  
T Matrix ◽  
The Cross ◽  
Three Body

In this paper, we study the in-medium nucleon–nucleon (NN) cross-section by using the Dirac–Breuckner–Hartree–Fock approximation (DBHF) with T-matrix project technique for determining the nucleon self-energy. By solving Thompson equation for different partial-wave states separately, we find that the discrepancies of nucleon self-energies in various T-matrix project representations are dominated by the channels with smaller angular momentum. Although the cross-section is independent on the project of T-matrix, the medium suppression of the cross-section in various T-matrix representations are apparently different due to the self-consistency of DBHF calculation involving effect mass of nucleon as an iterative parameter. Our results also show that the cross-sections in the complete pseudovector (CPV) choices are larger than those obtained with both DBHF in the pseudoscalar (PS) choice and nonrelativistic Brueckner–Hartree–Fock with three-body force (BHF + 3BF), respectively. Further comparison shows that the neutron–proton (NP) cross-section within DBHF + PV approach, [Formula: see text], is approximately equal to and slightly larger than that evaluated with BHF + 3BF, [Formula: see text], while the neutron–neutron (NN) (or proton–proton (PP)) cross-section given by DBHF + PV method, [Formula: see text], being the closest to the cross-section calculated by using BHF without 3BF in the lower energy region. Additionally, the discrepancies of the in-medium nucleon–nucleon differential cross-section induced by different representations of T-matrix in DBHF are discussed for nuclear matter with different densities.

Autoionization resonances in the argon iso-electronic sequence

2012 ◽  
Vol 90 (6) ◽  
pp. 547-555 ◽  
Author(s):  
Juby George ◽  
G.B. Pradhan ◽  
Milind Rundhe ◽  
Jobin Jose ◽  
G. Aravind ◽  
...  
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Ionic Species ◽  
Theoretical Studies ◽  
Isoelectronic Sequence ◽  
Quantum Defect Theory ◽  
Theoretical Results ◽  
Good Agreement

We report results of theoretical studies of 3s → np and 2s → np autoionization resonances, respectively, in the 3p and the 2p photoionization cross sections of a few members (Ar, K+, Ca2+, Fe8+, Zn12+, and Kr18+) of the argon isoelectronic sequence, within the framework of the relativistic random phase approximation and using the relativistic multichannel quantum defect theory. The present approach would enable analysis of complex atomic spectra especially of atomic and (or) ionic species that are found in stellar gases in a computationally economical way. The shape profiles of the autoionization resonances have been analyzed in the present work using appropriate Fano parameters. The quantum defects determined for some of the lower or intermediate excited states are found to be in good agreement with the experimental and (or) theoretical results.

scholarly journals Nucleon form factors at threshold

2019 ◽  
Vol 218 ◽  
pp. 04003
Author(s):  
Alexandr Milstein
Keyword(s):  
Invariant Mass ◽  
Cross Section ◽  
Cross Sections ◽  
Mass Spectra ◽  
Form Factors ◽  
Invariant Mass Spectrum ◽  
Nucleon Form Factors ◽  
The Cross ◽  
Good Agreement ◽  
Invariant Mass Spectra

The pp¯invariant mass spectra in the processes e+e−→ pp¯, e+e−→ nn¯, J/ψ → pp¯ω, J/ψ → pp¯ρ, and J/ψ → pp¯γ close to the pp¯is discussed. The optical potentials for NN¯pair in the superposition of S and D waves (due to tensor forces) at spin unity of the pair, as well as for NN¯pair in the S wave at spin zero of the pair, are proposed. The parameters of the potentials are obtained by fitting the cross sections of NN¯scattering together with the pp¯invariant mass spectra in e+e−→ pp¯annihilation and J/ψ decays. Good agreement with the available experimental data is achieved. Using our potential and the Green’s function approach we also describe the cross section of e+ e−→ 6π and the η’π+ π− invariant mass spectrum in the decay J/ψ → γη’π+π− in the energy region near the NN¯threshold.

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