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Recent and Current Program of the NIST Atomic Spectroscopy Data Centers:
Critically Evaluated Data and Bibliographies on Atomic Spectra -
Energy Levels, Wavelengths, Transition Probabilities, and Line Shapes


The Atomic Spectroscopy Data Centers: Atomic Energy Levels and Wavelengths and the Atomic Transition Probabilities and Spectral Line Shapes critically review, compile, and disseminate data on energy levels, wavelengths and line classifications, transition probabilities and oscillator strengths, and line shapes and radiative lifetimes for the spectra of atoms and atomic ions in all stages of ionization. The NIST data centers also publish annotated bibliographies and maintain files on bibliographic references categorized by element, stage of ionization, and technical content. The centers also maintain online Atomic Spectroscopy Databases

Bibliographic Databases and Data Center Publications
Available online is the Atomic Transition Probability Bibliographic Database and the Atomic Spectral Line Broadening Bibliographic Database. There is also a searchable list of Data Center Publications including critical compilations, databases, reviews, and bibliographies produced by the data centers.
Energy-Level and Wavelength Compilations
Energy-level data have been recently compiled for O II, all spectra of the elements Na through S, the iron-period elements K through Ni, all spectra of Cu, Zn, Ge, Kr, Mo, and 63 spectra of the rare-earth elements, La through Lu.

Wavelength compilations based on these energy-level data have been published for O II and all spectra of Mg, Al, S, and Sc, with all wavelength regions being covered. A compilation of wavelength data for high-ionization spectra of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Kr, and Mo has been published.

Work is complete on the Handbook of Basic Atomic Spectroscopic Data, which gives wavelengths and intensities for some 11,000 of the stronger lines of the neutral and singly ionized atoms of 99 elements (H through Es, Z = 1-99) along with energy levels and transition probabilities (where available). This is now in press and will be made available in three media forms; an electronic book (eBook), Web database, and as a published handbook.

Wavelength and energy-level compilations for Ne I and all spectra of Ga, and Ar are almost complete. Work is continuing on new or updated energy-level and wavelength compilations for spectra of other elements from hydrogen through argon (Z = 1 to 18) and completion of the noble gases (Ne, Ar, Kr, Xe) monograph. Work is beginning on the alkaline-earth metals (Rb, Sr, Ba), tungsten, and Ni-like spectra.

Transition Probability Compilations  
Recent critical compilations of atomic transition probabilities cover the iron-group elements Sc through Ni and the light elements C, N, and O. Also, a recent update of the tables previously published in the CRC Handbook of Chemistry and Physics contains about 8300 selected lines of all elements for which reliable data are available, mostly for neutral and singly ionized atoms. A compilation for neutral and singly-ionized barium has been completed and is now in press.

A critical compilation of prominent lines of neutral and singly ionized heavy atoms is now being updated, and work is also continuing on evaluating data for the remaining atoms and ions of H through Ne and Na through Ca. For these spectra, calculations from the Opacity Project play a major role.

Recent Line Shapes and Shifts Compilations
Comprehensive critical reviews have been published for experimental Stark widths and shifts for neutral and ionized atoms. These recent reviews cover the time period from 1976 to 1988.
Numeric Databases
The Atomic Spectra Database (ASD) includes most of the existing critically evaluated NIST data on atomic energy levels, transition probabilities, and wavelengths compiled by the Atomic Spectroscopy Data Centers that are reasonably up-to-date. ASD provides interactive capability that allows the user to choose the element or elements of interest and the type of data to be displayed. Default formats are also available for quick viewing of the data. The database provides full search and filter capabilities. Data are included for about 950 spectra and about 70,000 energy levels. There are wavelengths for about 91,000 lines from 1 Å to 200 µm, with transition probabilities and estimated uncertainties for about half of these. Energy level data are available for most ions of the elements from H through Kr (Z = 1 to 36), Mo (Z = 42), as well as the first five stages of ionization of the lanthanides (Z = 57 to 71). Wavelength data are available for all elements up to Es (Z = 1 to 99). For spectra of H through Ni (Z = 1 to 28) the wavelengths are accompanied by line classifications and transition probabilities. Wavelength data from recent comprehensive NIST compilations of the spectra of Mg, Al, S, Sc, Be I, O II, and Ne I are also included. For the first five spectra of other elements, wavelengths and relative intensities for prominent lines without classifications as originally published in Wavelengths and Transition Probabilities for Atoms and Atomic Ions (NSRDS-NBS 68) and reprinted annually in the CRC Handbook of Chemistry and Physics are given. References to the NIST compilations and original data sources are listed in a bibliography.

Other Atomic Spectroscopy Databases are currently available (platinum, ionization energies, bibliographies) and new databases have recently been made available online Spectral Data for the Chandra X-ray Observatory and Handbook of Basic Atomic Spectroscopic Data.