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      XrayDB: X-ray Reference Data in SQLite
      =======================================

This project provides the file xraydb.sqlite, an SQLite3 database of atomic
data, characteristic X-ray energies and X-ray cross sections for the elements.
The project began with the data from the compilation of Elam, Ravel, and
Sieber[1].  More data has since been added.

The xraydb.sqlite can be used directly with sqlite3 or with any programming
language that has an SQLite library.  No further installation is needed. See
http://sqlite.org for further details.

Because some of the components of the database hold arrays of numbers (for
example, coefficients for interpolation), the arrays are stored in the database
as JSON-encoded strings, and will need to be unpacked to be used.  For
reference, see http://json.org.

For some programming languages, higher-level wrappers may be provided to give
an even easier interface to these data.

Directory Contents
-------------------

The file xraydb.sqlite containes the SQLite database, and can be use
immediately, without any changes or further installation.

Other files and directories in this distribution may be of interest:

    Directory           Contents
    ---------           --------
    src/                raw source text files, and scripts (mostly in python)
                        to create the database.
    periodic_table/     latex (with tikz package) and python source to generate
                        a poster-sized periodic table of the elements with X-ray
                        edge and emission line energies from the database.
    wrappers/python     a Python wrapper for this database.

Database Contents
------------------

The XrayDB database includes the following data (from Elam, Ravel, and Sieber[1]
except where noted):

  * Atomic Symbol, Atomic Number, Atomic Mass, Density of pure element.

  * Energies, Fluorescence yield, and Jump ratio for K, L, M, N, O,
    and P core electroni levels of the elements.

  * Energies, Siegbahn and IUPAC symbols, initial and final core levels,
    and relative intensity of the fluorescence lines for the elements.

  * Coefficients for calculating the photo-electric absorption
    coefficient (mu) as a function of X-ray energy for the elements.

  * Coefficients for calculating the coherent and incoherent scattering
    cross-sections as a function of X-ray energy for the elements.

  * Energy levels, Partial and Total transition probabilities for the
    Coster-Kronig transitions (Auger processes in which the empty core
    level is filled from an electron in a higher level with the same
    principle quantum number).

  * Widths of the core level widths (from Keski-Rahkonen and Krause[2])

  * coefficients to calculate elastic scattering cross-section,
       f0(q) (from Waasmaier and Kirfel[3]).

  * anomalous X-ray scattering factors (f', f''), and absorption
    cross-sections (mu) compiled by Chantler et al[4].

In general, cross-sections are in cm*cm/gr, and energies are given in eV.
Energy-dependent data for cross-sections is typically valid in the range
from about 250 eV to about 200,000 eV.

See the documentation for the database schema, and for further references.

References
-----------

The data from Elam, Ravel and Sieber is itself a compilation from other sources.
The Data/elam.dat file (and the documentation for xraydb) contains amore complete
 set of references.

[1] W. T. Elam, B. D. Ravel and J. R. Sieber, Radiation Physics and Chemistry 63 (2),
    pp121–128 (2002) [http://dx.doi.org/10.1016/S0969-806X(01)00227-4].
[2] O. Keski-Rahkonen and M. O. Krause, Total and Partial Atomic-Level Widths,
    Atomic Data and Nuclear Data Tables 14, pp139-146 (1974)
[3] D. Waasmaier and A. Kirfel, New Analytical Scattering Factor Functions for Free
    Atoms and Ions, Acta Crystallographica A51, pp416-431 (1995)
    [http://dx.doi.org/10.1107/S0108767394013292].
[4] C. T. Chantler, Journal of Physical and Chemical Reference Data 24, p71 (1995)