Electron capture and loss by fast fluorine atoms in collisions with rare gas targets

1988 ◽  
Vol 66 (11) ◽  
pp. 972-977 ◽  
Author(s):  
B. Hird ◽  
F. Rahman ◽  
M. W. Orakzai
Keyword(s):  
Cross Sections ◽  
Rare Gas ◽  
Rare Gases ◽  
Single Atoms ◽  
Positive Ions ◽  
Electron Transfer Theory ◽  
The Cross ◽  
Fluorine Ions ◽  
Gas Targets ◽  
Pass Through

Cross sections are reported for the production of fast negative fluorine ions in collisions between a neutral fluorine beam and single atoms of each of the rare gases, at collision energies between 20 and 110 keV. The energies at which the cross sections pass through a maximum fit very well with the Massey criterion, assuming a simple electron-transfer theory. The cross sections for the production of fast fluorine positive ions are also reported. These are found to be smallest for the heavy targets and reach a maximum in helium and neon, which have higher ionization potentials than fluorine.

Electron transfer measurements from rare gas targets to O12+ ions between 60 and 200 keV

1980 ◽  
Vol 58 (6) ◽  
pp. 772-778 ◽  
Author(s):  
B. Hird ◽  
S. P. Ali
Keyword(s):  
Cross Sections ◽  
Spin Symmetry ◽  
Rare Gas ◽  
Final States ◽  
Rare Gases ◽  
Product Ions ◽  
The Cross ◽  
Gas Targets ◽  
Crossing Theory ◽  
Relative Weighting

Charge exchange measurements in thin targets of the rare gases by an O2+ beam have been made between 60 and 200 keV. Taking into account the relative weighting of the final states which are allowed assuming spin, symmetry, and Λ conservation it was found that a crossing theory of the Landau–Zener type is completely inadequate to account for the cross sections of the heavier targets, whereas a non-crossing theory in the Rapp–Francis formulation was found to give good fits, both in energy dependence and overall magnitude, to the cross sections except for the xenon target where it is too small by a factor of 2. The improvement in fit is due to the inclusion of a factor which was omitted in the original formulation of Rapp–Francis, and also the inclusion of many states of the product ions in the calculation.

Stueckelberg-Landau-Zener-(SLZ)-Modell für atomare Stoßprozesse / Stueckelberg-Landau-Zener-(SLZ) Model for Atomic Scattering Processes

1973 ◽  
Vol 28 (10) ◽  
pp. 1642-1653
Author(s):  
G.-P. Raabe
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Wave Functions ◽  
Differential Cross Sections ◽  
Rare Gases ◽  
Radial Wave ◽  
Atomic Scattering ◽  
The Cross

Scattering processes of atoms, molecules and ions with two crossing electronic potentials may be treated in the Stueckelberg-Landau-Zener-(SLZ) model. In this paper the WKB-solutions for the radial wave functions, given by Stueckelberg are used to calculate differential cross sections. The effects on the cross sections are explained in a semiclassical picture, following the procedures of Ford and Wheeler, and Berry. In the scattering of H+ by rare gases, some effects in the elastic cross sections are observed which can be explained by the influence of the potential of the chargeexchanged particles, using the SLZ-model. The structure in the elastic cross sections for H2+-Kr can be explained as a rainbow structure with superimposed Stueckelberg oscillations.

Collisional electron detachment and decomposition cross sections for SF−6, SF−5, and F− on SF6 and rare gas targets

1989 ◽  
Vol 91 (4) ◽  
pp. 2254-2260 ◽  
Author(s):  
Yicheng Wang ◽  
R. L. Champion ◽  
L. D. Doverspike ◽  
J. K. Olthoff ◽  
R. J. Van Brunt
Keyword(s):  
Cross Sections ◽  
Rare Gas ◽  
Electron Detachment ◽  
Gas Targets

Electron loss cross sections from rare gas atoms to Ar+

1982 ◽  
Vol 60 (7) ◽  
pp. 977-980
Author(s):  
B. Hird ◽  
S. P. Ali
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Rare Gas ◽  
Electron Loss ◽  
Rare Gases ◽  
Thin Target ◽  
Rare Gas Atoms ◽  
Good Agreement

Measurements of the σ10 cross section for a beam of Ar+ ions of energies between 30 and 120 keV passing through a thin target of the rare gases show good agreement with the few previous measurements in this energy region.

scholarly journals Floating Ice Transport Conditions at the Cross-Sections Between Pier Columns in Open Ice-Water Two-Phase Flow Canals

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1813
Author(s):  
Xiangpeng Mu ◽  
Juan Bao ◽  
Yunfei Chen
Keyword(s):  
Cross Sections ◽  
Empirical Equation ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Hydraulic Conditions ◽  
Ice Conditions ◽  
The Cross ◽  
Pass Through ◽  
Ice Water

Floating ice is easy to jam at the cross-sections contracted by bridge pier, gate pier, etc., in ice-water two-phase flow canals. To solve the problem, the critical hydraulic conditions of floating ice transport at the cross-sections between pier columns were explored in this study. Based on the generalized physical model of the cross-sections between pier columns of water transfer canals, the movement and transport characteristics of floating ice in front of the pier columns were studied under different hydraulic conditions and ice conditions, and the critical hydraulic conditions necessary for floating ice to pass through the cross-sections between pier columns were analyzed. Moreover, dimensional analysis and regression analysis were carried out in order to establish an empirical equation for calculating the critical water flow Fr (Froude number) for the floating ice to be transported through the cross-sections between pier columns, thus providing a basis for the ice jam risk assessment and hydraulic regulation of ice-water two-phase flow canals, as well as control of the emergent ice drainage of canals during freezing periods.

Net ionisation cross sections of rare gas targets in collisions with swift highly charged ions

1993 ◽  
Vol 126 (1-4) ◽  
pp. 21-24 ◽  
Author(s):  
A. Cassimi ◽  
J. P. Grandin ◽  
L. H. Zhang ◽  
A. Gosselin ◽  
D. Hennecart ◽  
...  
Keyword(s):  
Cross Sections ◽  
Highly Charged Ions ◽  
Rare Gas ◽  
Gas Targets ◽  
Charged Ions

Single electron capture by N12+ in rare gas targets between 60 keV and 200 keV

1979 ◽  
Vol 57 (12) ◽  
pp. 2078-2083
Author(s):  
B. Hird ◽  
H. C. Suk ◽  
S. P. Ali
Keyword(s):  
Cross Section ◽  
Weighted Average ◽  
Rare Gas ◽  
Rare Gases ◽  
Single Electron Capture ◽  
Correct Energy ◽  
Type Calculation ◽  
Gas Targets ◽  
Singly Charged ◽  
Charged Ions

Charge exchange measurements in thin targets of the rare gases by a N2+ beam have been made between 60 keV and 200 keV. The singly charged ions produced in the collisions are expected to be produced in only a few allowed states, and a Rapp and Francis type calculation for the weighted average cross section to these allowed states was found to have generally the correct energy dependence but to be too small by a factor which increased from 4 in He to more than 10 in Xe. There was some evidence that the 4P state of N2+ may have been present in the beam in varying amounts.

Neutron Cross Sections for Some Threshold Reactions

1965 ◽  
Vol 20 (12) ◽  
pp. 1583-1587 ◽  
Author(s):  
Torbjörn Lagerwall
Keyword(s):  
Cross Sections ◽  
Fission Neutron ◽  
High Energy ◽  
Rare Gas ◽  
Coincidence Method ◽  
Rare Gases ◽  
Fission Neutron Spectrum ◽  
Neutron Reactions ◽  
Neutron Cross Sections ◽  
Gas Isotopes

Three neutron reactions leading to production of the rare gases Ar41 and Xe135 have been investigated. Single crystal samples of KF, CaF2, and BaF2 were irradiated in the Berlin reactor and the target-free absolute activities of the rare gas isotopes measured by a β-γ-coincidence method. The calculated cross sections areK41(n,p) Ar41: σ= ( 2,73±0,41) mb; σ0= (98,6±14,8) mb;Ca44 (n,a)Ar41: σ = (61,1 ±9,2) μb; σ0= (64,7± 9,7) mb;Ba138(n,a)Xe135: σ= ( 1,9 ±0,3) μb; σ0= ( 4,9± 0,7) mb.The first set of values are valid for a fission-neutron spectrum. The second set are calculated cross sections for the high energy plateau. They can be considered as valid for 15 MeV neutrons.

Studies of Energy Transfer and Ionization Processes in a Helium ICP

1987 ◽  
Vol 41 (4) ◽  
pp. 621-624 ◽  
Author(s):  
H. B. Fannin ◽  
C. J. Seliskar ◽  
D. C. Miller
Keyword(s):  
Population Distribution ◽  
Rare Gas ◽  
Rare Gases ◽  
Reduced Pressure ◽  
Plasma Energy ◽  
Neutral Gas ◽  
Positive Ions ◽  
Population Distributions ◽  
Rare Gas Atoms ◽  
Ionization Behavior

The spectral consequences of the introduction of varying concentrations of heavy rare gas atoms into a reduced-pressure helium ICP have been examined. A term-dependent quenching of He(I) emission was observed and is consistent with previous work on a kinetic model for this ICP. In addition, the ionization behavior of the added rare gases has been studied, and a simple rule seems to emerge from the results: the first ionization potential of helium represents an upper bound to the plasma energy available (probably through collisional processes) to excite and/or ionize added species. Although spectroscopic temperatures can be calculated from the state population distributions for the added neutral gas atoms, the fact that the values vary with concentration and with the chemical identity of the species betrays the fact that the plasma is not in local thermodynamic equilibrium with respect to neutral atoms. Quite differently, the results for plasma positive ions show the same statistically determined spectroscopic temperatures; thus, it appears that these ions are nearly equilibrated and also suprathermal in population distribution.

Ionization by positive ions

1957 ◽  
Vol 240 (1222) ◽  
pp. 382-395 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Ion Beam ◽  
Ionization Cross ◽  
Secondary Electrons ◽  
Positive Ions ◽  
Adiabatic Theory ◽  
The Cross ◽  
Low Pressures

We describe a method of measuring the ionization cross-section of atoms by positive ions, in which electrons are collected from single collisions of an ion beam passing through a gas at low pressures. Secondary electrons formed by the collisions of ions with surfaces are suppressed. Measurements are given for twenty-three cases, over energy ranges of ~ 5 to ~ 40 keV (§ 1) and ~ 100 to ~ 3 keV (§2). The cross-sections do not appear to conform to the simple adiabatic theory, but the size of cross-section in the adiabatic region appears to depend upon the reduced mass of the system.

Sign in / Sign up

Export Citation Format

Share Document