Importance of coupling for inelastic collisions between protons and hydrogen atoms

1965 ◽  
Vol 283 (1392) ◽  
pp. 100-114 ◽  
Keyword(s):  
Cross Sections ◽  
Intermediate State ◽  
Relative Velocity ◽  
Inelastic Collisions ◽  
Hydrogen Atoms ◽  
Resonance Reactions ◽  
The Cross ◽  
Good Agreement

The importance of coupling for fast collisions between protons and hydrogen atoms is examined with the two-centred expansion in atomic eigenfunctions proposed by Bates (1958 a ). Cross-sections are evaluated for reactions H + + H (I s ) → H(I s ) + H + , H + + H( I s ) → H(2 s ) + H + , and H + + H(l a ) → H + + H(2 s ). The effect of a single intermediate state, either I s or 2 s , is considered. For the non-resonance processes, it is found that the cross-sections may be substantially increased by passage through intermediate state for incident energies less than about 10 keV, tending towards equality with decrease in relative velocity. Results obtained for the symmetrical resonance reactions are in good agreement with the two-state solutions of McCarroll (1961).

Inelastic collisions between excited alkali atoms and molecules. VI. Sensitized fluorescence in mixtures of sodium with CH4, CD4, C2H2, C2H4, and C2H6

1969 ◽  
Vol 47 (12) ◽  
pp. 1249-1252 ◽  
Author(s):  
M. Stupavsky ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Inelastic Collisions ◽  
Fluorescent Light ◽  
Molecular Gas ◽  
Sodium Vapor ◽  
Total Cross Sections ◽  
Sensitized Fluorescence ◽  
Alkali Atoms ◽  
The Cross ◽  
Good Agreement

The total cross sections for 32P1/2–32P3/2 mixing in sodium, induced in collisions with CH4, CD4, C2H2, C2H4, and C2H6 molecules, have been determined using the method of sensitized fluorescence. The sodium vapor – molecular gas mixtures were irradiated with each NaD component in turn, and the cross sections were obtained from measurements of relative intensities of the two D components present in the fluorescent light. The cross sections are as follows. For CH4: Q12(2P1/2 → 2P3/2) = 148 Å2, Q21(2P1/2 ← 2P3/2) = 77 Å2; for CD4: Q12 = 151 Å2, Q21 = 81 Å2; for C2H2: Q12 = 182 Å2, Q21 = 96 Å2; for C2H4: Q12 = 178 Å2, Q21 = 94 Å2; for C2H6: Q12 = 182 Å2, Q21 = 95 Å2. The cross sections Q21 are in good agreement with the values calculated according to the theory of Callaway and Bauer.

Inelastic collisions at low energies

1969 ◽  
Vol 47 (10) ◽  
pp. 1723-1729 ◽  
Author(s):  
A. Dalgarno
Keyword(s):  
Energy Loss ◽  
Cross Sections ◽  
Low Energy ◽  
Inelastic Collisions ◽  
Low Energies ◽  
Low Energy Electrons ◽  
The Cross ◽  
Loss Rates

A summary is presented of the processes by which low energy electrons lose energy in moving through the atmosphere and estimates are given of the cross sections and energy loss rates. The mechanisms by which thermal electrons cool are described and the cooling efficiencies are listed.

Elastic and inelastic scattering of 40 MeV polarized protons from 90Zr and 92Zr

1979 ◽  
Vol 57 (4) ◽  
pp. 540-549 ◽  
Author(s):  
R. de Swiniarski ◽  
Dinh-Lien Pham ◽  
G. Bagieu ◽  
H. V. Geramb
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Imaginary Component ◽  
Spin Orbit ◽  
Model Calculations ◽  
Analyzing Powers ◽  
Elastic And Inelastic Scattering ◽  
Polarized Protons ◽  
The Cross ◽  
Good Agreement

Analyzing powers and cross sections have been measured for elastic and inelastic scattering of 40 MeV polarized protons from 90Zr and 92Zr. The analysis has been carried out in the DWBA within the framework of the macroscopic and microscopic models. Furthermore, the coupled-channels calculations using the vibrational model and the full Thomas form for the spin–orbit potential give a very good description for both the cross sections and the analyzing powers of the iow-lying2+, 3−, 5−, and 4+ states in 92Zr and the 2+ and 3− in 90Zr. The cross section and analyzing power for the first 2+ state in these nuclei were compared with previous results at 30 and 20.3 MeV, and from this comparison a certain energy dependence of the relative strength of the spin–orbit deformation to the central deformation could be observed. Microscopic model calculations with tensor and spin–orbit components included in the projectile–target real interaction and with an exact treatment of knock-on' exchange have been performed for the 2+ states in these nuclei. An attempt has also been made in order to include the imaginary component in the N–N interaction. For these calculations, rather good agreement was obtained especially for the 2+ state in 92Zr but poor agreement for 90Zr. Finally, valence plus core polarization calculations have also been done and showed a very good agreement between theory and experiment for those 2+ transitions.

SENSITIZED FLUORESCENCE IN VAPORS OF ALKALI METALS: VIII. ENERGY TRANSFER BETWEEN THE 4 2P LEVELS IN POTASSIUM INDUCED BY INELASTIC COLLISIONS

1966 ◽  
Vol 44 (4) ◽  
pp. 753-768 ◽  
Author(s):  
G. D. Chapman ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Alkali Metals ◽  
Inelastic Collisions ◽  
Inert Gases ◽  
Inert Gas ◽  
Vapor Pressures ◽  
Sensitized Fluorescence ◽  
Potassium Vapor ◽  
The Cross ◽  
Scattering Cross Sections

Sensitized fluorescence in potassium vapor and its mixtures with inert gases was investigated in order to determine cross sections for the inelastic collisions leading to excitation transfer between the 4 2P1/2 and 4 2P3/2 states in potassium. The study was carried out at potassium vapor pressures of about 10−6 mm Hg, which were not formerly accessible to such experiments, and in the absence of radiation trapping. The cross sections Q1(4 2P1/2 → 42P3/2) and Q2(4 2P1/2 → 4 2P3/2) are as follows: for K–K collisions: 370 and 250 Å2; for K–He: 60 and 41 Å2; for K–Ne: 14 and 9.5 Å2; for K–A: 37 and 22 Å2; for K–Kr: 61 and 41 Å2; for K–Xe: 104 and 72 Å2. These values supersede those published previously (Chapman, Krause, and Brockman 1964; Chapman and Krause 1965). The cross sections for collisions between potassium and inert gas atoms do not increase monotonically with the polarizabilities of the inert gases but behave similarly to the electron – inert gas elastic scattering cross sections. This behavior is interpreted on the basis of a semiclassical model for the interaction, which involves overlap forces.

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  

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.

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