scholarly journals Application of the Screened Hydrogenic Model to Light Atoms

2021 ◽  
Vol 09 (03) ◽  
pp. 131-143
Author(s):  
Robert W. Smithwick
Keyword(s):  
Light Atoms ◽  
Hydrogenic Model

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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 ).

Refinement of light atoms in heavy atom structures*

1971 ◽  
Vol 133 (133) ◽  
pp. 150-167 ◽  
Author(s):  
Effi Huber-Buser
Keyword(s):  
Heavy Atom ◽  
Light Atoms

The Interaction of Light Atoms with Small Molecular Clusters

2000 ◽  
Author(s):  
Paul J. Dagdigian ◽  
Millard H. Alexander
Keyword(s):  
Molecular Clusters ◽  
Light Atoms

Partially Unrestricted Hartree—Fock Calculations of Light Atoms

1965 ◽  
Vol 43 (11) ◽  
pp. 4184-4185 ◽  
Author(s):  
J. F. Perkins
Keyword(s):  
Hartree Fock ◽  
Light Atoms

PHONON BROADENING OF IMPURITY SPECTRAL LINES: II. APPLICATION TO SILICON

1963 ◽  
Vol 41 (11) ◽  
pp. 1823-1835 ◽  
Author(s):  
Robert Barrie ◽  
Kyoji Nishikawa
Keyword(s):  
General Theory ◽  
Spectral Lines ◽  
Deformation Potential ◽  
Phonon Interaction ◽  
Potential Description ◽  
Electron Phonon Interaction ◽  
Shallow Impurity ◽  
Hydrogenic Model ◽  
Numerical Estimations

The general theory of the phonon broadening of impurity spectral lines discussed in an earlier paper is applied to shallow impurity levels in silicon. With the use of a modified hydrogenic model and a deformation potential description of the electron–phonon interaction, expressions are obtained for typical contributions to the half-widths. Some numerical estimations are made for both acceptor and donor cases and are compared with experiment.

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