RADIS describes itself as ‘a fast line-by-line code for high resolution infrared molecular spectra’. My project focussed on adding support for atomic line databases to RADIS, which has up till now catered only for molecular databases. Atomic lines differ significantly from molecular lines in how they are affected by Lorentzian broadening and how non-equilibrium spectra are handled.

• The Einstein A coefficient is now used directly for calculating the non-equilibrium linestrength, given that it is calculated anyway for non-equilibrium spectra where it isn’t already present, rather than removing the temperature-dependent component of the reference linestrength, which was found to result in some atomic spectra not appearing. This also removes the need to calculate the reference linestrength for databanks where it’s not already present.
• Removed some redundnant code and miscellaneous fixes and improvements.
• Fixed the documentation for many parts of the new code for atomic spectra so the formatting appears correct on Read the Docs.
• The pull request for the implementation of the Kurucz database has been merged
• Work has started on adding support for the NIST atomic database and it is currently at a stage where it produces working spectra.

• Support has been added for non-equilibrium spectra. Comparisons with SpectraPlot are still showing discrepancies, the source of which is not yet resolved.
• References have been added for the Kurucz databank
• Miscellaneous minor improvements and fixes in the code and docs

• Tests have been added for the implementation of the Kurucz database and associated parts of the code
• Examples have been added relating to the Lorentzian broadening of atomic lines and partition functions.
• The function to parse Kurucz linelists has been re-written based on Pandas.
• The precision of some parts of the code has been improved by using numpy.expm1 rather than numpy.exp, thereby showing weaker spectra that otherwise weren’t being seen
• Support has been added for loading existing databanks of atomic species without specifying the species initially.
• A greater range of formats are now accepted as input to specify the species for which to calculate a spectrum.
• Documentation for atomic spectra and the Kurucz database has been updated further

Support has been added for the species-specific partition functions that are usually included along with the new linelists. In doing so, a new config parameter was added to allow the user to enable RADIS to automatically modify the local database files and update the config file accordingly.

Stark broadening for atomic lines has been implemented with different temperature scalings for neutral and ionised radiators.