Charge transfer in the presence of a radiation field

1998 ◽  
Vol 76 (3) ◽  
pp. 245-250 ◽  
Author(s):  
S -M Li ◽  
J -G Khou ◽  
Z -F Zhou ◽  
J Chen ◽  
Y -Y Liu
Keyword(s):  
Charge Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Atomic Hydrogen ◽  
Capture Cross ◽  
Exchange Collision ◽  
Increasing Functions ◽  
Theoretical Results ◽  
Capture Cross Sections

In the first Born approximation, the dressing modification in laser-assisted charge exchange collision is investigated. The crosssections for electron capture by a proton from dressed atomic hydrogen and dressed helium targets are calculated within awide energy range. Theoretical results show that with impact energy increasing, the dressing effect leads to increasingly significant cross-section modifications. The modified capture cross sections are increasing functions of the ratio of laser strength to frequency. PACS Nos.: 34.50.Rk; 34.70.+e; 32.80.Wr; and 34.90.+q

scholarly journals Positron Impact Excitation of the nS States of Atomic Hydrogen

Atoms ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
Anand K. Bhatia
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Atomic Hydrogen ◽  
Impact Excitation ◽  
Orbital Method ◽  
Positron Impact ◽  
Excitation Cross Sections ◽  
Theoretical Results ◽  
Incident Positron

The excitation cross sections of the nS states, n = 2 to 6, of atomic hydrogen at various incident positron energies (10.23 to 300 eV) were calculated using the variational polarized-orbital method. Nine partial waves were used to obtain converged cross sections. The present results should be useful for comparison with results obtained from other theories and approximations. The positron-impact cross section was found to be higher than the electron-impact cross sections. Experimental and other theoretical results are discussed. The threshold law of excitation is discussed and the cross sections in this region were seen to obey the threshold law proportional to ( ln k f ) − 2 . Cross sections were calculated in the Born approximation also and compared to those obtained using the variational polarized orbital method.

ELECTRON CAPTURE CROSS SECTIONS

1954 ◽  
Vol 32 (6) ◽  
pp. 393-405 ◽  
Author(s):  
Harry Schiff
Keyword(s):  
Electron Capture ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Alpha Particles ◽  
Electron Interaction ◽  
Capture Cross ◽  
The Cross ◽  
Singly Charged ◽  
Capture Cross Sections

Electron capture cross sections are calculated in the first Born approximation for alpha particles passing through hydrogen and singly charged helium ions passing through helium using the complete interaction Hamiltonian. Estimations of captures into excited states are made with the help of the partial cross sections obtained in a simple closed form using only the (incident ion)−(electron) interaction. The results indicate that the first Born approximation, using the complete interaction, is quite adequate in the velocity range given by [Formula: see text]. An impact parameter calculation for protons in hydrogen shows that the cross section obtained using only the (incident ion)–(electron) interaction gives unphysical results at low velocities [Formula: see text], and that most of the contribution to the cross section arises from impact parameters p > a0, where a0 is the radius of the first Bohr orbit in hydrogen.

THERMAL NEUTRON CAPTURE CROSS-SECTION OF Na23 AND Mn55

1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Thermal Neutron Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Capture Cross Sections

The thermal neutron capture cross sections of Na23 and Mn55 have been determined using the activation method. The values are 0.53 ± 0.03 and 12.7 ± 0.3 barns respectively with respect to σAul97 = 93 barns. These agree well with recent pile oscillator results. The half-life for Mn56 is found to be 2.576 ± 0.002 hr.

scholarly journals Сечения образования ионов He-=SUP=-+-=/SUP=- в различных электронных состояниях при столкновениях ионов He-=SUP=-2+-=/SUP=- с атомами водорода

2020 ◽  
Vol 90 (6) ◽  
pp. 895
Author(s):  
А.А. Басалаев ◽  
В.В. Кузьмичев ◽  
М.Н. Панов ◽  
О.В. Смирнов
Keyword(s):  
Kinetic Energy ◽  
Electron Capture ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Precision Measurements ◽  
Capture Cross ◽  
Hydrogen Atoms ◽  
Hydrogen Target ◽  
Degree Of Dissociation ◽  
Capture Cross Sections

Using collision spectroscopy based on precision measurements of the kinetic energy of projectile ions that capture an electron, we measured the state selective electron capture cross sections of formation of He^+(n) ions at collision 3^He^{2 +} ions with an energy of E = 1.4-10 keV/a.m.u. with hydrogen atoms. The atomic hydrogen target with a degree of dissociation 78% at a temperature of tungsten dissociation cell 2180K has been made.

MEASURING CAPTURE CROSS SECTIONS FOR HEAVY-ELEMENT PRODUCTION

2004 ◽  
Vol 13 (01) ◽  
pp. 293-300
Author(s):  
NEIL ROWLEY ◽  
NABILA GRAR
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Reaction Path ◽  
Superheavy Element ◽  
Evaporation Residue ◽  
Capture Cross ◽  
Total Capture ◽  
Capture Cross Sections

The creation of the nucleus of a superheavy element follows an extremely complex reaction path starting with the crossing of an external potential barrier (or distribution of barriers). This is followed by the evolution towards an equilibrated compound nucleus, which takes place in competition with pre-compound-nucleus fission (quasi-fission). Once formed the equilibrated compound nucleus must still survive against true fusion to yield a relatively long-lived evaporation residue. Much of this path is poorly understood, though recently, progress has been made on the role of the entrance-channel in quasi-fission. This will be briefly reported and a method proposed to measure the total capture cross section for such systems directly.

THE CAPTURE CROSS-SECTION FOR THERMAL NEUTRONS OF CADMIUM, LITHIUM6, BORON10, BARIUM, MERCURY AND HYDROGEN

1941 ◽  
Vol 19a (3) ◽  
pp. 33-41 ◽  
Author(s):  
E. L. Harrington ◽  
J. L. Stewart
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Capture Cross Section ◽  
Comparison Method ◽  
Thermal Neutrons ◽  
Capture Cross ◽  
Scattering Effect ◽  
Capture Cross Sections

A comparison method of measuring, by using solutions, the capture cross-sections for thermal neutrons is described. The chief advantages are directness, simplicity, and freedom from uncertainties as to direction of path, or as to the magnitude of the scattering effect. The method is best suited to nuclei of large cross-sections. Assuming the well checked value for the cadmium nucleus to be correct, the capture cross-sections of certain other nuclei were determined. The results for barium and for hydrogen differ widely from values previously published.

Electron-capture cross sections for low-energy highly charged neon and argon ions from molecular and atomic hydrogen

1985 ◽  
Vol 31 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Cüneyt Can ◽  
Tom J. Gray ◽  
S. L. Varghese ◽  
J. M. Hall ◽  
L. N. Tunnell
Keyword(s):  
Electron Capture ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Low Energy ◽  
Capture Cross ◽  
Argon Ions ◽  
Capture Cross Sections

Meyer-Neldel Rule in Deep-Level-Transient-Spectroscopy and its Ramifications

2003 ◽  
Vol 763 ◽  
Author(s):  
Richard S. Crandall
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Capture Cross ◽  
Emission Data ◽  
The Cross ◽  
Transient Spectroscopy ◽  
Capture Cross Sections

AbstractThis paper presents data showing a Meyer-Neldel rule (MNR) in InGaAsN alloys. It is shown that without this knowledge, significant errors will be made using Deep-Level Transient-Spectroscopy (DLTS) emission data to determine capture cross sections. By correctly accounting for the MNR in analyzing the DLTS data the correct value of the cross section is obtained.

REACTOR NEUTRON CAPTURE CROSS SECTION OF 51-DAY Sr89

1957 ◽  
Vol 35 (10) ◽  
pp. 1215-1219 ◽  
Author(s):  
L. P. Roy ◽  
J. C. Roy
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
High Flux ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Naturally Occurring ◽  
Reactor Spectrum ◽  
Capture Cross Sections

The neutron capture cross section of Sr89 has been measured by an activation method. Naturally occurring strontium was irradiated in different high flux positions in the NRX reactor at Chalk River and the amount of Sr90 formed by successive neutron capture in Sr88 was determined by separating and measuring its daughter Y90. Using values of 36.6 and 0.005 barns for the respective neutron capture cross sections of Co59 and Sr88, the capture cross section of Sr89 for reactor spectrum neutrons was found to be 0.49 ± 0.10 barn.

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