NIST Atomic Spectra Database

• Energy levels of He I and He-like ions from Li⁺ to Ds¹⁰⁹⁺ have been added/updated (about 5000 values added).
• Wavelengths and transition probabilities of forbidden lines of Fe II have been added/updated.
• Energy levels of neutral iodine (I I) have been updated.
• Ionization energy of Cm I has been updated.
• Two A-values in Si I have been corrected (lines at air wavelengths 2443.36 Å and 2452.12 Å).
• Designations of 3 levels in Eu I have been corrected.
• The misprinted J value (J = 1) of one level of Cu IV at 306941.8 cm⁻¹ has been corrected to J = 2.
• A misprint in the term label of one level of Rb III at 222301.41 cm⁻¹ has been corrected.
• The letter "x" has been deleted from the label "x ³F^o" of one odd-parity term of Fe I with levels above 50000 cm⁻¹. This term label was mistakenly duplicated in the previous versions of ASD. We thank Jeff Valenti of Space Telescope Science Institute for reporting this error.
• The bug causing some lines to be omitted in the multiplet output format has been corrected.
• Displaying oscillator strengths for forbidden transitions has been enabled.
• The Lines input form has been significantly modified to streamline the search for wavelengths, energies, or transition frequencies.
• A new graphical feature has been added to the Lines input form: an output of a spectral image in the visible range.
• Several minor bugs fixed.

• Energy levels, spectral lines, and transition probabilities updated and extended for C II, Fe VII, Ac I-III.
• Energy levels and spectral lines inserted for ¹²C II, ¹³C II, and ¹⁴C II.
• A typo in the energy of the 1s²2s9p ¹P^o₁ level in Be I has been corrected.
• A misprint in the Landé g-factor value of one Yb II level (22960.80 cm⁻¹) has been corrected.
• Transition probabilities of Rb I updated.
• Ionization energies of C II, Fe VII, Se I, Dy I, Tm I, Rn II, Ac I, Cf I, Ni XX, Ge XXIII updated.
• A misprint in the 4d¹⁰5s5d ³D₃ energy level of Cd I corrected.
• Configuration labels corrected for several levels in Ni II, Rb IV, Rh II-III, In III, Ba III, Nd II, Hf I, Y IV, Xe II, Bi II. These errors were detected by Jon Grumer of Lund University, Sweden, whose help is gratefully acknowledged.
• Energy levels and spectral lines updated/extended for Ni XIX-XX, Kr IX, Kr XVIII-XXXVI and for all hydrogen-like spectra of elements from He to Ds, including the isotope ³He. For all H-like spectra, transition probabilities have been updated or added from the data of O. Jitrik and C. Bunge 2004 (JPCRD 33, 1059), which have been rescaled to the 2018 CODATA values of the fundamental constants and to the AME2016 atomic masses (M. Wang et al. 2017, Chin. Phys. C 41, 030003) with the use of the same isotopes as in the energy-level calculations of V. A. Yerokhin and V. M. Shabaev 2015, JPCRD 44, 033103.
• Energy units of Hartree and GHz added to the choice of units for output of energy levels in Levels, Lines (including the multiplet layout and Grotrian diagram), and Ionization Energies sections of ASD.
• A new option added for the intensity scale choice in LIBS and Saha-LTE plots (energy flux or photon counts). The new default setting is to display spectral intensities on a scale proportional to energy flux. Prior to this change, intensities displayed by both the Saha-LTE and LIBS plots were proportional to photon counts.
• Lines and levels Holdings pages updated to display the ASD content for isotopes.
• Several minor bugs fixed.

• Transition probabilities of some E2 transitions corrected for He I, Li II, Be III, and B IV. Some of the previous values from J.R. Fuhr and W.L. Wiese, J. Phys. Chem. Ref. Data 39, 013101 (2010) that were quoted from M. Godefroid and G. Verhaegen, J. Phys. B 13, 3081 (1980) were in error by a factor of 10⁵, which was previously overlooked.
• Energy level assignments added for 53 lines of O I.
• Energy levels, spectral lines, and transition probabilities added/updated for Ni V and Hf I.
• Observed wavelengths and their uncertainties corrected for Ac I. They were slightly wrong in the previous version of ASD due to a technical error.
• Added CSV and ASCII tab-delimited output formats to the Ionization Energies database output.
• Minor bugs fixed.

• Landé g-factors added/updated for V I.
• Ionization energy updated for Lr I.
• Two E2 transition probabilities corrected for Cr V.
• Energy levels, spectral lines, and transition probabilities added/updated for Fe III, Y VIII, Bi III, and Ac I-III.
• Energy levels and spectral lines updated for Be I. Wavelength uncertainties added for Be II.
• The energy conversion factors changed to the 2018 CODATA fundamental constants.
• LIBS queries have been optimized for speed. Advanced options have been added to LIBS interface, including the ability to model spectra of any ionization stage.
• Minor bugs fixed in the LIBS software.

• Line intensities and transition probabilities of Pt I updated.
• Energy levels updated and spectral lines and transition probabilities added/updated for Pt II and Ir II.

• Lines and transition probabilities of Cd II added/updated.
• Ionization energy updated for Zr I, Te I, Hg III, Pm I, No I, Po I.
• Lines/levels added/updated for Sr I.
• Energy levels, spectral lines, and transition probabilities added/updated for Pt I.
• An error in Saha-Boltzmann equations used in Saha-LTE plots and in LIBS plots has been corrected. This error was due to omission of the partition function for fully-ionized atoms (bare nuclei) and led to overestimated fractional abundance of hydrogen-like ions or hydrogen atoms in a hot plasma. Database queries have been optimized, which resolved the problem of slow response in LIBS plots.
• Minor bugs are fixed in various codes.

• Designations and percentage compositions of three levels in Fe II updated/corrected.

• Options for downloading the output in ASCII tab-delimited and CSV formats added to both the Levels and Lines input forms.
• Ionization energy updated for Pd I, C II-III, Si VI-IX,XI.
• A misprint in one level of Zn XXI corrected.
• Energy levels and spectral lines added/updated for F I, Ne I, Sc I, Zn I, Xe I, Re III-V, Os III, Bi I.
• Spectral lines, transition probabilities and energy level classifications added/updated for F I, Ne I, Ar I, K I, Sc I, Zn II, As I, Br I, Kr I, Nb IV, Y VII, In I, Xe I, Re III-V, Os III, Au I, Bi I.
• Transition probability references and accuracy codes updated for Ga I.
• Minor bugs are fixed in various codes.

• Error correction in Saha-LTE and LIBS plots: in all versions prior to this, division by partition function was accidentally omitted in the procedure calculating the line intensities, leading to incorrect relative intensities of lines belonging to different ions.

• The corrected bug affected the calculation of Saha-LTE plots when user selected units of eV for the output energy levels (in Advanced Output Options for Lines).
• Corrected a small typo in the file libshelp.html.

• Corrected the multiplet output for gA.

• Corrected calculation of Saha ionization balance (ASD and LIBS)
• Ionization energy updated for Pd I, C II-III, Si VI-IX,XI.
• A misprint in one level of Zn XXI corrected.

• Grotion diagram functionality has been redesigned and is no longer dependent on Java.

• Energy levels and spectral lines added/updated for Sn III.
• Missing energy-level classification corrected for one line of Pt V.
• Bugs in various codes have been fixed, including the Grotrian diagrams, which are now supported for Internet Explorer only.
• Minor improvements in styles and graph layouts.

• A new interface to ASD for Laser-Induced Breakdown Spectroscopy (LIBS) has been created.
• Output pages of Levels, Lines, and Ionization Energies sections of ASD have been modified to display the uncertainties of the data. Critically evaluated information on measurement uncertainties is currently available for about 50 % of the ASD data. When the wavelength data are requested in standard air, the uncertainties displayed incorporate contributions resulting from conversion of vacuum wavelengths to air. When the energy level data are requested in units other than cm⁻¹, the displayed uncertainties incorporate contributions from uncertainties of the conversion factors.
• Designations corrected for some energy levels of Dy II.
• Transition probabilities updated/corrected for Sr II and Zr III.
• Energy levels, spectral lines, and transition probabilities added/updated for C I, Cu II, V I-II, Y V, Pt VI-VIII.
• Energy levels and spectral lines with classifications added for 12C I and 13C I.
• Ionization energy updated for C I, V II, Zr I, Y V, Lu II, Ce II, Pr II, Nd II-IV, Pm II-IV, Sm II-IV, Eu II-IV, Gd II-IV, Tb II-IV, Dy II-IV, Ho II-IV, Er II-IV, Tm II-IV, Yb IV, Hf II-III, Lr II-III, Rf I-IV.
• Spectral lines, energy level classifications and transition probabilities added/updated for La I-II and Ce I-II.
• A few minor errors in data and programming have been corrected.

• Energy levels, lines, and transition probabilities added/updated for Co III, Sr II, Zr VI, Pt IV-V, Ir IV, Pb I, Ra I-II.
• Line classifications and transition probabilities added/updated for Y I-II, Mo I, Rh I, Nd II, Eu I, Pr II, Dy I, Tm I, Lu I, Ta I, Ir I, Pb I.
• Ionization energies updated for Zr VI, Nd III, Pm III, Sm III, Lu III, Ra II.
• One energy level corrected for Se XIX.
• Designations and percentage compositions corrected for J = 1 odd-parity levels of Bi II quoted from Y. N. Joshi and M. Mazzoni, Phys. Lett. A 118, 237 (1986).
• Transition probability accuracy and bibliographic references updated for Cu I-II, Zn I-II, Ge I-II, Cd I-II, Sn I, Cs I, Hg I, Tl I, U I.
• Line (observed wavelength) references to NIST Monograph 8 (T. Shirai et al., 2000) have been replaced with references to original data sources for about 10000 lines of Ti III-XXI, V IV-XXI, Cr V-XXII, Mn VI-XXIII, Fe VIII-XXIV, Co VIII-XXV, Ni IX-XXVI, Cu X-XXVII, Mo VII-XLI.
• A few minor errors in data and programming are corrected.

• A new feature added to Lines Search: output of line-ratio data for diagnostics of electron temperature and density in plasmas. Plasma diagnostics data are included for C III,V; N III,IV,VI; O III-V,VII; Ne III-VII,IX; Mg II,V-IX,XI; Si IV,VII-XI,XIII; S IV,VI,IX-XIII,XV; Ar IV,XI-XIV; Ca VI,XIII-XVI; Fe XII,XX; Ni XIV.
• Saha-Boltzmann plots have been modified by adding an experimental feature allowing the user to specify a multi-element mixture.
• Conversion factors from energy units of cm⁻¹ to eV and Ry changed to the CODATA 2014 values.
• Ionization energies updated/corrected for C I, C IV, Cl I, Mn I, Zn I, Br III, VI; Kr III, Cd I, In I, Sn II, Rn XXIII, Th II, Lr I.
• Energy levels and wavelengths added/updated for Sn II, Mo V, W VIII, Th I-III. Energies of the three 3s6d ³D levels of Mg I changed to the previously published values from W. C. Martin and R. Zalubas, J. Phys. Chem. Ref. Data 9, 1-58 (1980).
• Transition probabilities added/updated for Sn II, Mo V, W VIII, F V-VIII, Ne VI-IX and updated/corrected for Cl II and Mg I.
• Transition probability references to NIST Monograph 8 (T. Shirai et al., 2000) have been replaced with references to original data sources for several thousand lines of Ti III-XXII, V IV-XXIII, Cr V-XXIV, Mn VI-XXV, Fe VII-XXVI, Co VIII-XXVII, Ni IX-XXVIII, Cu X-XXIX, Kr V-X,XVIII-XXXVI, Mo VI-XXXV,XXXVIII-XLII.
• Procedure for obtaining partition functions of H and D are corrected to remove level double-counting.
• A number of minor errors in data and programming are corrected.

• New interactive triangular data holdings diagrams added to the Lines and Levels Holdings web pages. The holdings can also be accessed directly from these links for lines and levels.
• Line sorting routines corrected in the database codes.
• Error corrected in Saha-LTE ionization balance calculations, related to choice of a correct ionization limit in spectra with multiple limits.
• Energy levels and spectral lines with classifications added/updated for Cr I-II and Cu I.
• Energy levels, spectral lines, and transition probabilities added or updated for Fe V.
• Transition probabilities added or updated for Al I-VII.
• Line identifications corrected for Mn VI, Kr II, Rb X, Fr I
• Observed and/or Ritz wavelengths corrected for O VII, Ne V, Ca I, Fe XV, Ag III, Xe IV, W I near the boundaries of the air wavelength range (2000 and 20000 Å).
• Line strength and transition probability corrected for several forbidden transitions, two in C V, two in N VI, and three in O VII.
• Several misprints corrected in various other spectra.

• Wavelengths of ~200 unidentified lines of Fe I corrected.
• Line references for Ne III corrected for all observed lines.
• Errors in A values corrected for Sc I-II.
• Energy levels and spectral lines added/updated for Ca III, Mn II, Fe II, Co II, Ag II, and In II.
• Ionization Energies output page changed to display the ion charge instead of the spectrum number.
• Levels and Lines Lists of Holdings modified to display triangular charts in addition to periodic table charts.
• Several misprints corrected in various spectra.

• Added a new Web interface for retrieval of ionization energies and total binding energies of ground states of all atomic spectra. Ionization energies and ground states added or revised for all spectra of all elements up to Ds (Z = 110). About 4900 of those ionization energies (5844 in total) are new, and about 400 have been updated. Uncertainties have been added or revised for all ionization energies.
• Web interface of ASD is improved. Handling of the Spectrum field in Levels and Lines Search Forms is revised to conform to the standard used in the NIST Atomic Spectra Bibliographic Databases, which allows for searching of multiple spectra by isoelectronic sequence names, as well as by names of spectra and by ionic charge. Layout of the lines output is changed to approximate layouts used in atomic spectroscopy literature. Help pages contents are revised.
• Energy levels and spectral lines with transition probabilities added/updated for Ne IV, Ti I-II, Sr II-XXXVIII, Cs III-LV, Ba III-LVI.
• Energy levels corrected or added for O VI, Pm II, Tb II, Dy I-II, Ho I, Tm II, Lu I, Hf I, Ta II, Au I-II, Hg III-IV, Tl II-IV, Pb I-V, Bi I-II, Bi VI, Po I.
• Energy level classifications added for prominent lines of Ge I-II, Ru II, Pd II, Nd I-II, Pm I-II, Sm I-II, Eu I-II, Gd I-II, Tb I-II, Dy I-II, Ho I-II, Er I-II, Tm I-II, Yb I-II, Lu I-II, Hf I-II, Ta I-II, Ir I-II, Au I-II, Tl I-II, Pb I-II, Bi I-II, Po I, At I, Rn I, Ra I-II.
• Transition probabilities added or updated for Tc I-II, Ru I-II, Pd I-II, In I, Sb I-II, I I, Nd I-II, Sm I-II, Eu I-II, Gd I, Tb II, Dy I-II, Ho I-II, Er I-II, Tm I-II, Yb I-II, Lu I-II, Hf I-II, Tl II, Pb I-II, Bi I-II.
• Missing observed intensities of 17 lines have been inserted from NIST Monograph 68 for Xe I.
• Several duplicate transitions deleted in the line lists for Na VII, Si I, Ar II, K I, Fe I, Sr I, Te I-II.
• A number of misprints corrected.
• Default unit for output wavelengths changed from Ångström to nm.

• Transition probabilities added/updated for S I-XV.
• Energy levels updated for Tc I, Ru II, Rh II, Ag I, Cd I, In I, Sn I, Sb I-II, Te I-II, I I.
• Spectral line lists updated for Tc I-II, Ru I-II, Rh I-II, Pd I-II, Ag I, Cd I, In I, Sn I, Sb I-II, Te I-II, I I-II, Cs II.
• Corrections made to line identifications and/or transition probability references for B III and Si I.
• A number of misprints corrected.

• Energy levels added for Ac III, Ag III, At I, Bi III-VI, Cd I-IV, Cs I-II, Hf I-II, I I-VIII, I XII-XIII, In I-V, Ir I-II, Nb I-VII, Nb XV, Os I-II, Pb I-II, Pd I-III, Po I, Pt I-II, Ra I-II, Re I-II, Rh I-III, Rn I-II, Ru I-III, Sb I-VI, Sn I-VI, Sr I-V, Sr XI-XII, Ta I-II, Tc I-II, Te I-VII, Tl I-II, Y I-V, Y XII-XIII, Zr I-II, Zr V-VI, Zr XIV.
• Energy levels updated for ¹⁹⁸Hg I, Ac I, Ag II, Ar II-III, Ar VII-XVII, Au I, Mo VI, W XIV, W XXIX, W XLI-LXXII.
• Spectral lines added for Ar XII, Ar XV-XVIII, W LII, W LIV, W LVI-LXXII.
• Spectral lines updated for ¹⁹⁸Hg I, Ar II-XI, Ar XIII-XIV, Mo VI, Sr I, W XIV, W XXIX, W XLIII-LI, W LV-LXIII, W LXV.
• A number of misprints corrected.
• Some programmatic improvements were made.

• Several misprints fixed.
• Minor improvement in the help system.

• Full integration with the NIST Atomic Spectra Bibliography Databases
• Added support of isotope data.
• Added energy levels for Ag I-II, Au I-II, Ac I-II, Bi I-II.
• Added or updated spectral lines and energy levels for H, B, Ne, Na, K, Kr in all ionization stages, Hg I, Fe I-II, highly-charged ions of W.
• Added spectral lines and energy levels for isotopes D, T, ³He I, ¹⁰B I-II, ¹¹B I-II, ¹⁹⁸Hg I and energy levels only for ³He II, ³⁹K I, ⁴⁰K I, ⁴¹K I.
• Added or updated transition probabilities for H through B in all ionization stages, C I-II, N I-II, Fe I-II.
• Updated conversion factors for transition probability parameters.
• A number of errors and/or misprints were fixed in various ions.

• Energies of the high-n ns and nd levels in Rb I corrected.
• Energies of the doubly-excited levels in Ar XVI corrected.
• Minor bug fixes.

• Ritz wavelengths and transition probabilities added for C VI and O VIII.
• Energy levels and lines added/updated for Br IV.
• Energy levels and lines added/updated for Ne V-VI.
• Numerous corrections for bibliographic references for transition probabilities and lines.
• Line 623.767 Å in Ar IV removed.

• Energy levels and lines added for Fr I (isotope ²¹²Fr).
• Energy levels and lines added/updated for ions of Ga.
• Comments field added for primary data source.
• Total Doppler-broadened spectrum output (summed over all ionization stages) added.

• Corrected vacuum-air conversions for the multiplet output.
• Observed wavelengths are now displayed for the singlet lines in the multiplet output.
• Level 6p^{2 3}P₂ in Hg I is assigned energy 96190 cm⁻¹.
• 15- and 100-page outputs are removed.
• Improved management of the popup windows (bibliography, etc.).
• Several other minor error fixes and corrections.

• Direct query links to bibliographic databases are added for both level and line queries.
• Citation information is now displayed on the query output pages.
• In He I, energy levels are corrected for 169 levels, Ritz wavelengths corrected for corresponding transitions.
• Duplicate level 1s3s ¹S₀ removed in N VI.
• About 100 duplicate lines removed in various ions of Mg, Al, B, P, and S.
• About 400 A-values corrected for Si II (×1e8).
• Energy corrected for the 2s²2p⁴ level in Ar XI.
• A number of references to transition probabilities and/or lines are corrected for ions of S, Mg, and Al.

• New comprehensive sets of data added for B II, Ne II-III, Ne VIII, Kr I-XXXVI.
• Data addition and updates for spectral lines of Al VI-XII and Si I-XIII.
• Energy levels for Nd II are updated.
• Level compositions added to Ho and Yb ions.
• Term grouping corrected in rare earth elements.
• Configuration notations corrected for 314 levels in Br I-II, Se XXIV, As XXIII, Dy II.
• Core J-values corrected in 2p⁵5f configuration in Al IV.
• J_cK notation corrected in some energy levels in Cl I.
• Primary source of data added in the output.
• Corrected observed/Ritz wavelength selection for line identification and Saha plots.
• Minor style interface improvements.

Si I energy levels from Energy Levels of Silicon, Si I through Si XIV, W.C. Martin and R. Zalubas, J. Phys. Chem. Ref. Data 12, 323-380 (1983) are now available.

Si I energy levels contained in the database through 12 March 1998 were from unpublished measurements and data compiled at NIST (1993), which updated the published NIST energy level compilation, Energy Levels of Silicon, Si I through Si XIV, W.C. Martin and R. Zalubas, J. Phys. Chem. Ref. Data 12, 323-380 (1983).

Pending completion and publication of the 1993 work, the Si I energy levels will revert back to the published data in the next release.