Version 1.3 of ASD is maintained as an archive. Version 2 contains significantly more data and offers many additional selection criteria and display options.
This service provides access and search capability to critically evaluated atomic spectroscopic data on energy levels, wavelengths, and transition probabilities. The Atomic Energy Levels Data Center and Data Center on Atomic Transition Probabilities and Line Shapes have carried out these critical compilations. Both Data Centers are part of the NIST Standard Reference Data program and located in the Physics Laboratory at the National Institute of Standards and Technology (NIST).
The following types of data are available for many common elements:
Warning: Your query may time out if you choose a stage with many holdings.
Note: If the holdings include no wavelength data for the spectrum you select, you may want to try the transition probabilities data for that spectrum if it is available; the wavelengths given with them may serve your purpose. The wavelengths will be ordered numerically if you select a wavelength range.
NIST Atomic Spectroscopic Database Query Results
Description of Energy Level Table Headings:
Spectrum: Stage of ionization. Config: Electronic configuration. Term: Term designation. J: J value. P: Parity, @ if odd, blank if even. Level: Energy level in cm-1, calculated value given if bracketed. g: Lande g value (magnetic splitting factor). Leading_percentages: Eigenvector percentage(s); squares of coefficients from the calculated eigenvector, multiplied by 100.Description of Wavelength Table Headings:
Spectrum: Stage of ionization. Int: Relative intensity. Observed: Observed wavelength (followed by "A" for Ångström) or observed wavenumber (followed by "cm-1" for inverse centimeter). Wavelengths below 2000 Å are vacuum values, with wavelengths in air being given for values above 2000 Å. A brace may appear for multiply classified lines. A "T" represents the wavelength is tentatively classified, and a "P" represents the wavelength is predicted along an isoelectronic sequence. Ritz: Calculated wavelength. Explanation as above for observed. Vacuum: Vacuum wavelength (followed by "A" for Ångström) calculated from the energy levels. Lower_Level: Lower energy level of the transition in cm-1. Upper_Level: Upper energy level of the transition in cm-1. Lower_Config: Lower configuration. Lower_Term: Lower term of the transition. Lower_J: Lower J value. Upper_Config: Upper configuration. Upper_Term: Upper term of the transition. Upper_J: Upper J value. Ref: Letter-numerical symbols listed are references for the observed wavelength values only. Multiplet: Multiplet number. If two are given, the Moore multiplet number will be in parentheses.Description of Transition Probability Table Headings:
Spectrum: Stage of ionization. Ty: Type of transition, allowed or forbidden (E1,E2,M1,M2) #: Multiplet number. M: An asterisk (*) indicates data are for the entire multiplet. Lower_Config: Lower configuration of the transition. Upper_Config: Upper configuration of the transition. Lower_Term: Lower term of the transition. Upper_Term: Upper term of the transition. Wavelength: Wavelengths are in Ångströms; vacuum wave- lengths are given below 2000 Å; wavelengths are in standard air 2000 Å and above. Calculated values are given with brackets. Lower_Level: Lower energy level of the transition in cm-1. Upper_Level: Upper energy level of the transition in cm-1. gi: Statistical weight of the lower level. gk: Statistical weight of the upper level. A_ki: Transition probability - allowed: 108 s-1; forbidden: s-1. F_ik: Absorption oscillator strength. S: Line strength (S-value) (atomic units). log_gf: Log gf. AC: Accuracy rating: A,B,C,D,E. Source: Source (reference number, sometimes accompanied with an abbreviation of: ls - LS coupling, n - normalized, or interp. - interpolation).
