L-shell ionization of atoms and their subsequent decay by radiative and non-radiative transitions

Pramana ◽  
1998 ◽  
Vol 50 (6) ◽  
pp. 669-681 ◽  
Author(s):  
P Venugopala Rao
Keyword(s):  
Subsequent Decay ◽  
Radiative Transitions ◽  
Shell Ionization

Multicharged Xei+ ions formed after de-excitation of inner-shell vacancies in Xe atom

2004 ◽  
Vol 82 (10) ◽  
pp. 811-818 ◽  
Author(s):  
Adel M El-Shemi
Keyword(s):  
Main Product ◽  
Fluorescence Yield ◽  
Monte Carlo Algorithm ◽  
Hole State ◽  
Radiative Transitions ◽  
Charge State Distributions ◽  
Nonradiative Transitions ◽  
Shell Vacancy ◽  
Shell Ionization ◽  
Vacancy State

Multicharged Xe ions following de-excitation of K-, L1-, L2,3-, M1-, M2,3-, and M4,5-subshell vacancies are calculated using a Monte-Carlo algorithm to simulate the vacancy cascade development. Fluorescence yield (radiative) and Auger and Coster–Kronig yields (nonradiative) are evaluated. The decay of the K hole state through radiative transitions is found to be more probable than through nonradiative transitions in the first step of de-excitation. On the other hand, the decay of L and M vacancies through nonradiative transitions are more probable. Ions, mainly produced from Xe in the K-shell vacancy state, are found to be Xe7+, Xe8+, Xe9+, and Xe10+. The charged Xe8+ ions predominate in the charge state distributions. The main product from the L1-shell ionization is found to be Xe8+ and Xe9+ ions, while the Xe8+ ions predominate at the L2,3 hole states. The charged Xe6+, Xe7+, and Xe8+ ions come mainly from 3s1/2 and 3p1/2,3/2 ionization, while Xe in 3d3/2,5/2 hole states becomes mainly Xe4+ and Xe5+ ions. The present results are found to agree well with the experimental data.PACS No.: 32.40.Hd

Recent Radiative and Collisional Atomic Data of Astrophysical Interest

1988 ◽  
Vol 102 ◽  
pp. 129-132
Author(s):  
K.L. Baluja ◽  
K. Butler ◽  
J. Le Bourlot ◽  
C.J. Zeippen
Keyword(s):  
Mass Production ◽  
Bound States ◽  
Physical Models ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Isoelectronic Sequence ◽  
Astrophysical Interest ◽  
Radiative Transitions ◽  
Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

SIGMAL: A Program for Calculating L-Shell lonization Cross-Sections

1981 ◽  
Vol 39 ◽  
pp. 198-199 ◽  
Author(s):  
R.F. Egerton
Keyword(s):  
Cross Sections ◽  
Fortran Program ◽  
Absorption Data ◽  
X Ray ◽  
Atomic Electrons ◽  
Energy Dependent ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Shell Ionization

SIGMAL is a short (∼ 100-line) Fortran program designed to rapidly compute cross-sections for L-shell ionization, particularly the partial crosssections required in quantitative electron energy-loss microanalysis. The program is based on a hydrogenic model, the L1 and L23 subshells being represented by scaled Coulombic wave functions, which allows the generalized oscillator strength (GOS) to be expressed analytically. In this basic form, the model predicts too large a cross-section at energies near to the ionization edge (see Fig. 1), due mainly to the fact that the screening effect of the atomic electrons is assumed constant over the L-shell region. This can be remedied by applying an energy-dependent correction to the GOS or to the effective nuclear charge, resulting in much closer agreement with experimental X-ray absorption data and with more sophisticated calculations (see Fig. 1 ).

The measurement of inner-shell ionization cross aections by electron impact in a TEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1266-1267
Author(s):  
Raynald Gauvin ◽  
Gilles L'Espérance
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Weight Fraction ◽  
Thin Foil ◽  
Specimen Thickness ◽  
Ionization Cross ◽  
Electron Dose ◽  
Total Electron ◽  
Inner Shell Ionization ◽  
Shell Ionization

Values of cross sections for ionization of inner-shell electrons by electron impact are required for electron probe microanalysis, Auger-electron spectroscopy and electron energy-loss spectroscopy. In this work, the results of the measurement of inner-shell ionization cross-sections by electron impact, Q, in a TEM are presented for the K shell.The measurement of QNi has been performed at 120 KeV in a TEM by measuring the net X-ray intensity of the Kα line of Ni, INi, which is related to QNi by the relation :(1)where i is the total electron dose, (Ω/4π)is the fractional solid angle, ω is the fluorescence yield, α is the relative intensity factor, ε is the Si (Li) detector efficiency, A is the atomic weight, ρ is the sample density, No is Avogadro's number, t' is the distance traveled by the electrons in the specimen which is equal to τ sec θ neglecting beam broadening where τ is the specimen thickness and θ is the angle between the electron beam and the normal of the thin foil and CNi is the weight fraction of Ni.

Approximate method for calculating the valance-shell ionization potentials

1992 ◽  
Vol 89 ◽  
pp. 915-930
Author(s):  
I Jano
Keyword(s):  
Approximate Method ◽  
Ionization Potentials ◽  
Shell Ionization

A SEMI-EMPIRICAL, FORMULA FOR THE TOTAL K-SHELL IONIZATION CROSS SECTION BY ELECTRON IMPACT

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-487-C9-490 ◽  
Author(s):  
C. JAKOBY ◽  
H. GENZ ◽  
A. RICHTER
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Empirical Formula ◽  
Ionization Cross Section ◽  
Ionization Cross ◽  
Semi Empirical ◽  
Shell Ionization

ON THE DETERMINATION OF COMPTON PROFILES BY ELECTRON INDUCED K-SHELL IONIZATION

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-819-C9-822
Author(s):  
K. MAHRT ◽  
P. ESCHWEY ◽  
H. GENZ ◽  
Y. MAO ◽  
A. RICHTER
Keyword(s):  
Shell Ionization

STIELTJES IMAGING TECHNIQUE APPLIED TO INNER SHELL IONIZATION PHENOMENA IN MOLECULES

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-769-C9-772 ◽  
Author(s):  
V. CARRAVETTA ◽  
H. AGREN
Keyword(s):  
Imaging Technique ◽  
Inner Shell Ionization ◽  
Shell Ionization

Energy levels and radiative transitions of Mg VII and Si IX

2021 ◽  
pp. 109439
Author(s):  
Yan Sun ◽  
Feng Hu ◽  
DongDong Liu ◽  
CuiCui Sang ◽  
MaoFei Mei ◽  
...  
Keyword(s):  
Energy Levels ◽  
Radiative Transitions

ENERGY-LOSS EFFECT IN K-SHELL IONIZATION

1998 ◽  
Vol 08 (04) ◽  
pp. 225-233 ◽  
Author(s):  
TAKESHI MUKOYAMA
Keyword(s):  
Energy Loss ◽  
Cross Sections ◽  
Relativistic Correction ◽  
Correction Method ◽  
Exact Integration ◽  
Plane Wave Born Approximation ◽  
Ionization Cross Sections ◽  
Energy And Momentum ◽  
Shell Ionization ◽  
Loss Effect

The energy-loss effect of the projectile for direct inner-shell ionization cross sections by charged-particle impact has been examined. The relativistic and nonrelativistic calculations for K-shell ionization with and without the energy-loss effect are made in the plane-wave Born approximation and compared with the Brandt-Lapicki theory for the corrections of the relativistic and energy-loss effect. It is demonstrated that the Brandt-Lapicki method gives a good approximation to both relativistic and nonrelativistic cross sections, which implicitly take into account the energy-loss effect. However, the use of the Brandt-Lapicki relativistic correction method in the nonrelativistic theory with the exact integration limits for energy and momentum transfer overestimates the relativistic calculations for low-energy projectiles. This indicates that the Brandt-Lapicki method for correction of the electronic relativistic effect should be used only with their energy-loss correction method.

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