scholarly journals Laser Assisted Charge Exchange in Atomic Collisions

1991 ◽  
Vol 11 (3-4) ◽  
pp. 285-290 ◽  
Author(s):  
J. F. Castillo ◽  
L. F. Errea ◽  
L Méndez ◽  
A. Riera
Keyword(s):  
Cross Section ◽  
Charge Exchange ◽  
Cross Sections ◽  
Laser Field ◽  
Laser Wavelength ◽  
Total Charge ◽  
Atomic Collisions ◽  
Radiative Transitions ◽  
The Cross ◽  
Impact Energies

We present total charge exchange cross sections for collisions of Li(1s22s2S) with H(1s) in presence of a linear polarized laser field of intensity 0.05 ≤ I ≤ 1 TW/cm2 and wavelength 5 103 ≤ λ ≤ 14 103 Å. Our calculation shows that the laser field can increase the cross section of this reaction by a factor of ten at impact energies E < 0.1 ke V/a.m.u. The mechanism of this process is discussed and it is shown that both atomic and molecular radiative transitions can take place depending on the laser wavelength employed.

Absolute cross sections for D2 Lyman and Werner band excitation by controlled electron impact

1984 ◽  
Vol 62 (1) ◽  
pp. 1-9 ◽  
Author(s):  
K. Becker ◽  
J. W. McConkey
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Impact Energy ◽  
Emission Cross Section ◽  
Direct Excitation ◽  
The Cross ◽  
Impact Energies

We have studied the Lyman [Formula: see text] and Werner [Formula: see text] band emissions produced by 20–500-eV electrons incident on molecular deuterium, D2. Emission cross sections of (3.7 ± 0.9) × 10−17 cm2 for the B → X and (3.54 ± 0.74) × 10−17 cm2 for the C → X system have been determined at 100-eV impact energy. Cascading did not play an important role in the [Formula: see text] emission, but it was shown to affect the [Formula: see text] emission seriously, particularly for impact energies below 50 eV. We estimate the cross section for direct excitation of the [Formula: see text] state and the cascade cross section to be 2.95 × 10−17 and 0.75 × 10−17 cm2, at 100 eV respectively. The cascade cross section is 20 ± 10% of the total B → X emission cross section, and is essentially constant in the energy range 300–50 eV, but increases significantly for lower impact energies, e.g., to 40 ± 15% at 27.5 eV. The cross section for the atomic 2p → 1s Lyman α emission from D2 has also been measured and the value of 1.00 × 10−17 cm2 at 100 eV is 20% smaller than the cross section for Lyman α emission from H2.

Ladungsaustausch zwischen Ionen und Atomen der Edelgase bei Stoßenergien unterhalb 200 eV

1969 ◽  
Vol 24 (11) ◽  
pp. 1716-1720
Author(s):  
H. Schlumbohm
Keyword(s):  
Cross Section ◽  
Charge Exchange ◽  
Cross Sections ◽  
Collision Energy ◽  
Threshold Energy ◽  
Strong Increase ◽  
Published Data ◽  
Slow Ions ◽  
Endothermic Process ◽  
The Cross

Charge exchange cross sections for the four systems He+, Ne+ + Ar, Kr have been measured, ap­plying slow ions gathering techniques. The values are several 1O-16 cm2 and are almost constant between 20 and 200 eV collision energy. The comparison with previously published data for charge exchange into optically excited higher states of the ions show that these reactions prefer at least at 25 to 30% endothermic channels instead of the exothermic one without excitation. - Additionally the cross section of the endothermic process Ar++Ne was measured. Above a threshold energy of 17 eV it shows a strong increase and a constant value of 7 · 10-17 cm2 between 20 and 200 eV.

scholarly journals Dissoziation von H2+ und H3+ beim Stoß an Kr im Energiebereich 6 – 60 keV / Dissociation of H2+ and H3+ by Collision with Kr in the Energy Range between 6 to 60 keV

1976 ◽  
Vol 31 (11) ◽  
pp. 1303-1307 ◽  
Author(s):  
B. Lehmann
Keyword(s):  
Radio Frequency ◽  
Energy Range ◽  
Cross Section ◽  
Charge Exchange ◽  
Cross Sections ◽  
Ion Source ◽  
Energy Curve ◽  
Gas Target ◽  
The Cross

Abstract H2+ and H3+ ions, produced in a H2 plasma of a radio-frequency ion source, were accelerated to 6-60 keV and directed into a gas target of Krypton. The cross sections for the formation of H+ and H- resp. H2+, H+ and H- have been measured. In the case of H+, obtained from the dissociation of H2+, 2 maxima have been found in the present energy range. A third is known to be at about 100 keV. We discuss the applicability of the Massey' adiabatic hypothesis, known from the analysis of charge-exchange experiments, to the maxima in the cross-section vs. energy curve for dissociation experiments.

Semi-classical treatment of atomic collisions

1970 ◽  
Vol 315 (1523) ◽  
pp. 465-478 ◽  
Keyword(s):  
Cross Section ◽  
Relative Motion ◽  
Cross Sections ◽  
Turning Point ◽  
Transition Matrix Element ◽  
Point Method ◽  
Collision Process ◽  
Atomic Collisions ◽  
Model Collision ◽  
The Cross

The semi-classical treatment of atom-atom collisions involving electronic transitions is discussed. As is well know n difficulties occur if the classical trajectories associated with the various states of importance in a collision process differ significantly. A method designed to overcome these is described. It will be referred to as the forced-common-turning-point method. The four coupled first-order differential equations which describe the new version of the semi-classical two-state treatment for an atom-atom collision may be reduced to a pair of generalized impact parameter equations. The first Born approximation to the cross-section obtained from the straightforward semiclassical treatment differs from the corresponding cross-section obtained from the full quantal treatment mainly in that it contains an anomalous multiplying factor equal to the ratio of the initial to the final velocity of relative motion. This anomaly does not arise with the forced-common-turning-point method. A model collision process which provides a very searching test is considered. Only two states are included. The initial interaction is zero, the final interaction is Coulombic and the transition matrix element is exponential. Curve-crossing may occur. The distorted wave approximation to the excitation cross-section may be found exactly and may also be computed using the forced-common-turning-point method. There is remarkable accord between the results. Thus in a case w here the reduced m ass of the colliding systems is 2 on the chemical scale, w here the excitation energy is 3.4 eV and where the incident kinetic energy of relative motion is only 0.85 eV above this the excitation cross-sections obtained differ by as little as 0.01 %; and, moreover, the patterns of the contributions to the cross-sections from the separate partial waves are similar.

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.

scholarly journals Asymptotic Behavior of Stable Structures Made of Beams

2021 ◽  
Author(s):  
Georges Griso ◽  
Larysa Khilkova ◽  
Julia Orlik ◽  
Olena Sivak
Keyword(s):  
Asymptotic Behavior ◽  
Cross Section ◽  
Cross Sections ◽  
Linear Elasticity ◽  
Circular Cross Section ◽  
Linear Elasticity Theory ◽  
Linear Elastic ◽  
The Cross ◽  
Small Rotation ◽  
Stable Structures

AbstractIn this paper, we study the asymptotic behavior of an $\varepsilon $ ε -periodic 3D stable structure made of beams of circular cross-section of radius $r$ r when the periodicity parameter $\varepsilon $ ε and the ratio ${r/\varepsilon }$ r / ε simultaneously tend to 0. The analysis is performed within the frame of linear elasticity theory and it is based on the known decomposition of the beam displacements into a beam centerline displacement, a small rotation of the cross-sections and a warping (the deformation of the cross-sections). This decomposition allows to obtain Korn type inequalities. We introduce two unfolding operators, one for the homogenization of the set of beam centerlines and another for the dimension reduction of the beams. The limit homogenized problem is still a linear elastic, second order PDE.

ISOSPIN DECOMPOSITION OF pp → NNππ CROSS SECTIONS — DO WE SEE A SIGN OF Δ(1600) EXCITATION IN THE nnπ+π+ CHANNEL?

2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Pion Production ◽  
Significant Contribution ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Theoretical Predictions ◽  
Order Of Magnitude ◽  
The Cross

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.

scholarly journals The Cross Section for the J = 0 → 2 Rotational Excitation of Hydrogen by Slow Electrons

1969 ◽  
Vol 22 (6) ◽  
pp. 715 ◽  
Author(s):  
RW Crompton ◽  
DK Gibson ◽  
AI McIntosh
Keyword(s):  
Momentum Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
The Cross ◽  
Excitation Processes ◽  
Slow Electrons ◽  
And Diffusion ◽  
Momentum Transfer Cross Section ◽  
Section Analysis

The results of electron drift and diffusion measurements in parahydrogen have been analysed to determine the cross sections for momentum transfer and for rotational and vibrational excitation. The limited number of possible excitation processes in parahydrogen and the wide separation of the thresholds for these processes make it possible to determine uniquely the J = 0 → 2 rotational cross section from threshold to 0.3 eV. In addition, the momentum transfer cross section has been determined for energies less than 2 eV and it is shown that, near threshold, a vibrational cross section compatible with the data must lie within relatively narrow limits. The problems of uniqueness and accuracy inherent in the swarm method of cross section analysis are discussed. The present results are compared with other recent theoretical and experimental determinations; the agreement with the most recent calculations of Henry and Lane is excellent.

scholarly journals Supplemental Material: Plate boundary trench retreat and dextral shear drive intracontinental fault-slip histories: Neogene dextral faulting across the Gabbs Valley and Gillis Ranges, Central Walker Lane, Nevada

2020 ◽  
Author(s):  
J. Lee ◽  
et al.
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Plate Boundary ◽  
Fault Slip ◽  
Cross Sectional ◽  
Walker Lane ◽  
Dextral Shear ◽  
The Cross

<div>Figure 6. Interpretative cross sections illustrating the cross-sectional geometry of several paleovalleys. See Figure 3 for location of all cross sections and Figure 8 for location of cross section CCʹ. Cross sections AAʹ and BBʹ are plotted at the same scale, and cross section CCʹ is plotted at a smaller scale. Figure 6 is intended to be viewed at a width of 45.1 cm.</div>

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