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Provides access to the holdings of NIST Physical Measurement Laboratory online data organized by element.
Contains NIST critically-evaluated data on atomic properties of the elements.
Contains values of the fundamental physical constants and a related bibliographic database.
Contains databases for energy levels, wavelengths, and transition probabilities for atoms and ions and related bibliographic databases.
Includes databases containing spectroscopic data for small molecules, hydrocarbons, and interstellar molecules. In addition, there are two publications containing equations and the underpinning theory for molecular spectroscopy.
Contains databases on thermophysical properties of gases, electron-impact cross sections (of atoms & molecules), potential energy surfaces of group II dimers, and atomic weights and isotopic compositions.
Contains databases on the interaction of x-rays and gamma-rays with elements and compounds.
This database calculates stopping-power and range tables for electrons, protons, or helium ions.
Contains a table of the half lives of 65 radionuclides and a database of the isotopic compositions, atomic weights and relative atomic masses of the elements.
This database consists of evaluated data for use in total-energy calculations of electronic structure by density-functional theory. It contains total energies and orbital energy eigenvalues for all atoms from hydrogen to uranium.
Provides access to all data sets at NIST.
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The use of International Units and the expression of uncertainty in measurement is critical to all data activities. For information on these topics, see guidelines for evaluating and expressing measurement uncertainty, and information on the International System of Units (SI).
Additional data and databases are being prepared for this Web site.
Online: June 1994
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