First Database for Atomic Spectroscopy Available from NIST

A computerized database for atomic spectroscopy will give physicists, chemists, astronomers, geologists and industry researchers easy access to the most comprehensive collection of accurate and critically evaluated atomic spectra available electronically.

The Database for Atomic Spectroscopy is now available from the Commerce Department's National Institute of Standards and Technology's Standard Reference Data Program. The DAS contains wavelengths, transition probabilities and energy levels for most ionization stages of 28 elements from hydrogen to nickel.

Every element has signature spectral lines that scientists can use to identify and quantify materials occurring in nature or in industrial processing laboratories. For example, astronomers use spectral lines from stars to determine which elements the star contains. Similarly, the semiconductor industry needs atomic spectral data when evaluating the characteristics of plasma gases used to etch semiconductors. Likewise, researchers studying the upper atmosphere use spectral data to monitor shifts in environmental conditions.

The DAS is an easy-to-use, menu-driven database designed for personal computers. Users can conduct searches for specific wavelengths, energy levels or elements. Users also can change the default options for units, output and other parameters as desired.

"The Database for Atomic Spectroscopy represents the best accumulated and critically evaluated data from decades of research," said Wolfgang Wiese, chief of NIST's Atomic Physics Division. "It gives uniform and balanced coverage of data on the first 28 elements of the periodic table."

The transition probabilities are taken from compilations of Wiese and his colleagues, including those in the CRC Handbook of Chemistry and Physics. The atomic energy levels are taken from compilations of the NIST Atomic Energy Levels Data Center or unpublished NIST data. Transition energy levels are taken from the NIST levels compilations. When levels for a transition are known, the indicated wavelength is calculated from them. A level list for a specified spectrum can be called up separately. The first version of DAS contains 27,000 spectral lines (from 1 to 200,000 angstroms in wavelength) and 45,000 energy levels.

Single copies of the DAS are available for $215. For more information or to order the DAS, contact the Standard Reference Data Program, A320 Physics Building, NIST, Gaithersburg, Md. 20899-0001, (301) 975-2208, fax: (301) 926-0416, email: SRDATA [at] enh.nist.gov (SRDATA[at]enh[dot]nist[dot]gov).

As a non-regulatory agency of the Commerce Department's Technology Administration, NIST promotes U.S. economic growth by working with industry to develop and apply technology, measurements and standards.