Introduction:

      The NIST X-ray Photoelectron Spectroscopy (XPS) Database gives easy access to the energies of many photoelectron and Auger-electron spectral lines.  Resulting from a critical evaluation of the published literature, the database contains over 22,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines.  A highly interactive program allows the user to search by element, line type, line energy, and many other variables.  Users can easily identify unknown measured lines by matching to previous measurements.

      Version 3.1 of the database included an expanded capability for displaying Wagner plots.   These plots can now be prepared for 42 elements.   In addition, mistakes were corrected in some data records.

      Version 3.2 implemented two new search and display options: Retrieve Auger Parameter data for selected elements and Retrieve Doublet Separation data for selected elements.

      Version 3.3 contained 3,000 additional data records.  The screen on which Wagner plots are displayed was redesigned to show median energies (for materials for which two or more binding energies or Auger kinetic energies are available) rather than to indicate the midpoints of the ranges as was done previously.  Wagner plots are now available for 50 elements.

      Version 3.4 included a new search and display option: Retrieve Data for a Selected Element.

      Version 3.5 implemented a software upgrade.

      Version 4.0 contained an additional 6,844 data records.

      Version 4.1 contains an additional 4,368 data records, as well as new reference photoelectron binding energies, reference Auger-electron kinetic energies, and reference Auger parameters for many elemental solids.  Wagner plots are now available for a total of 61 elements.  The new reference energies have been derived from analyses of Handbook data [Powell C.J., J. Electron Spectrosc. Relat. Phenom. 185, 1 (2012)] and are used in Calculations of Chemical Shifts.

      The following main search and display options are available (and click on the closed book icons at left to display additional choices):       Skip Navigation Links.

      Newly added data (since the release of version 2.0) contain considerable additional information about the specimen materials, the XPS measurement conditions, and the methods used to analyze the XPS measurements.   There may also be comments about the specimen morphology and the specimen treatments.   This information can be used to assess the significance of the reported data.   Finally, data have been included on surface core-level shifts.

      Interested scientists can use the last search option to check whether data from selected sources were included in the database.   Although computer searches were made of the scientific literature (using searches of key words such as XPS, X-ray photoelectron spectroscopy, X-ray photoemission, surface core-level shift, ESCA, and electron spectroscopy for chemical analysis in the title, abstract or key words of published papers), it is possible that papers with useful data may have been missed.   In such cases, NIST would appreciate being informed (by email to cedric.powell@nist.gov) of the relevant citations.

      Version 4.1 of the database contains data from papers published through 1996.  Help screens are available to guide the user, and descriptions are available of the various data fields.

      Versions 2.0 and 3.0 of the database contain data that have been standardized to a binding-energy scale for which the following lines and energies were used as calibrants: Au 4f7/2 = 84.00 eV, Ag 3d5/2 = 368.27 eV, Cu 2p3/2 = 932.67 eV, and C 1s (for hydrocarbon or hydrocarbon groups) = 284. 8 eV.  Work at the UK National Physical Laboratory [M. P. Seah, I. S. Gilmore, and G. Beamson, Surf. Interface Anal. 26, 642 (1998)] has led to small revisions of the calibration energies for the three noble metals.  The positions of these peaks vary slightly on the binding-energy scale depending on the X-ray source due to differences in X-ray spectral lineshapes.  The reported calibration energies vary for the Au 4f7/2 line between 83.95 eV and 83.96 eV, for the Ag 3d5/2 line between 368.21 and 368.22 eV, and for the Cu 2p3/2 line between 932.62 eV and 932.63 eV for a monochromatized aluminum Ka X-ray source, an unmonochromatized Mg Ka X-ray source, and an unmonochromatized Al Ka X-ray source.  Since the changes in the calibration energies for the three metals, approximately 0.05 eV, are small for most practical applications, it was decided not to make revisions at the present time to previous and newly added binding energies in the database to take account of the new calibration energies.

      Data have been included in the XPS database from papers in which specimen materials were in a well-defined physical and chemical state and in which at least one measurement was reported of the position of a calibration line on the instrumental binding-energy scale.   If any such measurement differed from the reference values, corrections were made to the reported energies as described in the help screen for Quality of Data.

      A description of the database design has been published [Lee, A. Y., Blakeslee, D. M., Powell, C. J., and Rumble, J. R., Data Science Journal 1, 1 (2002)].