News

The atomic line list has undergone extensive development since the last release. The software generating the line list, as well as the program doing the line selection for the web page have been replaced by 13,000 lines of new C++ code. All this work was necessary to restructure the internal data files and facilitate future upgrades of the line list. The primary goal will be to make the list complete for all elements, as far as data are available. This release starts this process by making the list complete for all 4th row elements. Future releases will start adding 5th, 6th, and 7th row elements. The second goal is to add more transition probability data from additional sources. Finally, an effort will be made to include observed wavelengths, especially for forbidden transitions. These are the most important user-visible changes that are implemented in this version:

• The atomic line list is now being distributed under a new copyright licence: the Creative Commons Attribution 4.0 International License.


• The web pages have been redesigned. The lines request form has been improved. An option for specifying the radial velocity of the emitting source has been added, thus making Doppler-shift corrections by hand unnecessary. Multiplet searches can now be done by simply clicking on the term field in the output. It is now possible to select lines based on the transition probability of the line. The maximum number of lines in the output has been increased to 5000. Multiple wavelength ranges can now be supplied at once.


• The output of the lines request form has been improved. The output will now always be correctly sorted, the search criteria are repeated in the output for later reference, and a few minor bugs have been solved. The columns in the output now have variable width to make the output easier to read (but there is an option to request fixed width columns like in version 2.04). Plain and LaTeX mode now produce truly HTML-free output when saved to disk. The atomic line list now has an option to show uncertainties for transition probabilities (where available).


• A new page for querying atomic levels has been added. Also a download section has been added, offering data files for the levels and lines in the atomic line list.


• Selection rules for intercombination, magnetic dipole (M1) and electric quadrupole (E2) transitions have been improved. Magnetic quadrupole (M2) and electric octopole (E3) transitions have been added to the list. This makes the list more accurate and complete.


• The theory for calculating level energies of hydrogenic ions has been fully updated following Section IV of Mohr, Taylor, & Newell, 2008, Rev. Mod. Phys. 80, 633. Furthermore, data for the following ions have been updated or amended: He I, Be II, Be III, C II, C IV, N V, O VI, Ne IV, Mg I, Mg II, Mg IV, Al IV, Cl II, Ar IX, Ca III, Sc II, Ti I, Ti XV, V I, V III, V IV, Cr I, Cr II, Cr XIV, Mn I, Mn III, Mn VII, Fe II, Fe III, Fe IV, Fe V, Fe VI, Fe VII, Fe XI, Fe XVI, Fe XVII, Fe XIX, Fe XXIII, Co XV, Ni II, Ni III, Ni X. Data for the elements Gallium through Krypton have been added. Transition probability data have been added from the NIST ASD v5.8 database (including uncertainties derived from the accuracy codes assigned by NIST), the MCHF/MCDHF collection (C.F. Fischer et al.), the second generation of semi-emperical log(gf) values by R.L. Kurucz (only partially complete), Taha Sochi (for C II), Romas Kisielius (for Zn II) and various sources for Fe III.