Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Atomic Spectroscopy Data Center


Critical compilations of atomic energy levels, transition wavelengths, and transition probabilities. Online databases.


The Atomic Spectroscopic Data Center at NIST provides the most comprehensive collection of atomic spectroscopy data in the world. We monitor scientific literature and maintain bibliographic databases of all papers containing spectroscopic data. By evaluating and compiling data on energy levels, transition probabilities, wavelengths, and lifetimes, we make it possible for researchers around the world to access these data quickly and efficiently. Our work is distributed though critically evaluated publications, stand-alone databases for PCs, and the World Wide Web.

Created February 23, 2010, Updated January 28, 2020