Elements

The JSON file containing most of the information on chemical elements is downloaded from the PubChem website : https://pubchem.ncbi.nlm.nih.gov/rest/pug/periodictable/JSON/?response_type=save&response_basename=PubChemElements_all

Units were added manually and column names have been modified.

You can access their interactive periodic table and find all relevent references here : https://pubchem.ncbi.nlm.nih.gov/periodic-table/#view=table.

X-Ray data

X-ray data are extracted from the X-RAY DATA BOOKLET.

References:

• J. A. Bearden, “X-Ray Wavelengths,” Rev. Mod. Phys. 39, 78 (1967).
• M. O. Krause and J. H. Oliver, “Natural Widths of Atomic K and L Levels, Ka X-Ray Lines and Several KLL Auger Lines,” J. Phys. Chem. Ref. Data 8, 329 (1979).

Isotopes

Isotope ground state properties are extracted from:

• API provided by the Nuclear Data Section of the Internationnal Atomic Energy Agency IAEA-NDS,
• NUDAT3

Levels and decays

Excited states and decay information are extracted from ENSDF and XUNDL databases.

Contributions to ENSDF are made by members of NSDD, the international network of Nuclear Structure and Decay Data evaluators.

Data update

The TkN database is automatically updated every month (the 15th) to take into account every new data releases from NUDAT3 and ENSDF/XUNDL