scholarly journals Forbidden transitions in excitation by proton impact in Li-like Al ions

2007 ◽  
Vol 25 (2) ◽  
pp. 277-282 ◽  
Author(s):  
V. Stancalie ◽  
V. Pais ◽  
M. Totolici ◽  
A. Mihailescu
Keyword(s):  
Cross Sections ◽  
Born Approximation ◽  
High Energy ◽  
Impact Excitation ◽  
Proton Impact ◽  
Collision Strength ◽  
Energy Behavior ◽  
Forbidden Transitions ◽  
Excitation Processes ◽  
The Impact

This paper presents cross-sections and collision strengths for proton-impact excitation of optically forbidden transitions in Al10+. These data, calculated in the impact-parameter formalism, covering the expected range of energies/temperature in laser-produced plasmas, are believed to represent the first such detailed treatment of this system. The cross-sections decrease with energy as E−1, while the collision strengths tend to finite limits as the energy of colliding proton becomes infinitely great. This high-energy limiting value has been evaluated combining results from the semi-classical treatment of ion-impact excitation processes and the Born approximation for high-energy behavior of the collision strength. The effective target size has been estimated from the calculated high-energy limit of the collision strength in the Born approximation.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

Investigating the impact of the partonic structure on the description of hadronic collisions at high energies

2020 ◽  
Vol 35 (22) ◽  
pp. 2050127
Author(s):  
M. Broilo ◽  
V. P. Gonçalves ◽  
P. V. R. G. Silva
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
High Energies ◽  
High Energy Behavior ◽  
Energy Behavior ◽  
The Impact ◽  
Hadronic Collisions

The impact of the partonic structure on the description of the hadronic cross-sections is investigated considering a multichannel eikonal model based on the Good–Walker approach. The total, elastic and single diffractive cross-sections are estimated considering different parametrizations for the parton distribution functions and the predictions are compared with the experimental data for proton–proton [Formula: see text] and antiproton–proton [Formula: see text] collisions. We show that the description of the high-energy behavior of the hadronic cross-sections is sensitive to the partonic structure.

Vacuum Ultraviolet Excitation of H(2p) by Electron Impact on H2

1972 ◽  
Vol 50 (18) ◽  
pp. 2211-2216 ◽  
Author(s):  
J. W. McConkey ◽  
F. G. Donaldson
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Vacuum Ultraviolet ◽  
High Energy ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Ultraviolet Excitation ◽  
A Value ◽  
High Energy Behavior ◽  
Energy Behavior

'Polarization-free' measurements are presented of the electron impact excitation of Lyman α by electron impact on H2 in the energy range 20–2000 eV. Cross sections are made absolute by normalizing to the data of Mumma and Zipf at 100 eV. A broad maximum in the function occurs around 60 eV, some 20 eV lower than was found by some previous workers. Reasons for this discrepancy are discussed. The high energy behavior of the cross section is analyzed in terms of the Bethe approximation and a value of 0.11 is obtained for the square of the dipole matrix element of the transitions involved.

scholarly journals TACHYON DYNAMICS OF THE BLACK DISC LIMIT IN THE HARD SMALL x PROCESSES IN QCD

2006 ◽  
Vol 21 (07) ◽  
pp. 549-558 ◽  
Author(s):  
B. BLOK ◽  
L. FRANKFURT
Keyword(s):  
Cross Section ◽  
Impact Parameter ◽  
High Energy ◽  
Black Disk ◽  
Black Disc ◽  
Energy Behavior ◽  
Small X ◽  
The Cross ◽  
The Impact ◽  
Black Disc Limit

We investigate the effective field theory (EFT) which gives the approximate description of the scattering of two hard small dipoles in the small x processes in QCD near the black disc limit (BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where α′P=0. We demonstrate that the high energy behavior of the cross-section depends strongly on the diffusion law in the impact parameter plane. On the other hand, almost threshold behavior of the cross section of the hard processes and multiplicities, i.e. fast increase of cross sections (color inflation), melting of ladders into color network and softening of the longitudinal distributions of hadrons are qualitatively insensitive to the value of diffusion in the impact parameter space. We evaluate α′P near the black disk limit and find significant α′P as the consequence of the probability conservation.

scholarly journals Electron Impact Excitation Cross Sections for B III

1983 ◽  
Vol 36 (5) ◽  
pp. 659
Author(s):  
PS Ganas ◽  
M Aryafar ◽  
LP Gately
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Cross Sections ◽  
Born Approximation ◽  
Oscillator Strengths ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Central Potential ◽  
Excitation Cross Sections ◽  
Generalized Oscillator

A realistic analytical central potential with two adjustable parameters is used to generate wavefunctions for the ground and excited states of doubly ionized boron. Generalized oscillator strengths and integrated cross sections from threshold up to 5 keY are calculated in the Born approximation for 2s-ns, 2s-np and 2s-nd excitations. Convenient analytic formulae for the cross sections are presented.

Construction of Constrained Dipole Oscillator Strength Distributions

2016 ◽  
Vol 230 (5-7) ◽  
Author(s):  
Ajit J. Thakkar
Keyword(s):  
Oscillator Strength ◽  
Cross Sections ◽  
High Energy ◽  
Strength Distribution ◽  
Sum Rule ◽  
Molar Refractivity ◽  
High Energy Behavior ◽  
Energy Behavior ◽  
Sample Application ◽  
Dipole Oscillator

AbstractA brief review is given of how a constrained dipole oscillator strength distribution (DOSD) is constructed from experimental and possibly theoretical photoabsorption cross-sections with constraints provided by molar refractivity data and the Kuhn–Reiche–Thomas sum rule. Some recent refinements including the imposition of the correct high-energy behavior on the DOSD for homoatomic molecules are discussed and extended to the general molecular case. A sample application to pyridine is given.

Electron–ion interactions for trapped highly charged Ge ions

2006 ◽  
Vol 84 (1) ◽  
pp. 67-81 ◽  
Author(s):  
G Machtoub ◽  
J.R. Crespo López-Urrutia ◽  
X Zhang ◽  
H Tawara
Keyword(s):  
Electron Beam ◽  
Cross Sections ◽  
Ion Trap ◽  
Dielectronic Recombination ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Theoretical Simulation ◽  
X Ray ◽  
New Information ◽  
Excitation Processes

A theoretical simulation of complex K X-ray spectra including those from dielectronic recombination and excitation processes is presented for trapped highly charged germanium ions ( Geq+, q = 27–30) interacting with a dense electron beam. We carried out numerical calculations of transition rates, level energies, transition wavelengths, resonance and collision strengths, and satellite intensity factors. Analytical results related to cross sections of B- through He-like Ge ions were obtained as well. The simulated spectra, including the contribution from different charge states of Ge27+–Ge30+, show good overall agreement over a wide electron energy range with the available X-ray measurements from the Heidelberg electron beam ion trap (EBIT). We have also predicted the electron impact excitation cross-section ratios for different transitions of Ge29+ and Ge30+ ions. It should be emphasized that the present analysis can also provide new information and clues of possible temperature measurements for EBIT and other plasma diagnostics.PACS No.: 32.30.Rj

Sign in / Sign up

Export Citation Format

Share Document