Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

NIST Standard Reference Database 71

NIST Electron Inelastic-Mean-Free-Path Database: Version 1.2

Last Update to Data Content: 1999    DOI:


This database provides values of electron inelastic mean free paths (IMFPs) for use in quantitative surface analyses by AES and XPS. The database can provide IMFP information from up to three types of sources: calculated IMFPs from experimental optical data for a limited number of materials, IMFPs measured by elastic-peak electron spectroscopy for some elemental solids, and IMFPs from predictive formulae for all materials. The calculated and measured IMFPs were generally reported in journal papers at specified electron energies and these IMFPs were fit with appropriate functions so that IMFPs could be found by interpolation at intermediate energies. 

Users may display/obtain IMFP values for elements, inorganic compounds, and organic compounds from the main menu. For a selected material in each class, the user can select a source of IMFPs (calculations, measurements, or predictive formulae) and then choose from a number of options for the energy range, IMFP units (manometers, Angstroms, and milligrams per square meter) and the type of display (linear, logarithmic, or linear/logarithmic coordinates).

Results may be displayed graphically; users can obtain an IMFP for a single electron energy, for multiple energies and can create an IMFP Table for regularly spaced electron energies. The IMFPs from the latter two options can be stored in files for later processing.

No charge.

Click here to download.

Please click here to view the PDF version of the Users' Guide.

Systems Requirements: Personal Computer operating on Windows 95, 98, 2000, Windows NT,Windows ME, Windows XP, Windows Vista, or Windows 7; hard disc space of 720 kilobytes minimum. 



Created August 27, 2010, Updated November 2, 2021