New atomic models for C, Si, S for use in solar UV radiative transfer calculations

Atomic models for C, Si and S in Lightweaver radiative transfer code format. Can be imported directly into Lightweaver. They are the same models used primarily to create the continuum synthetic spectrum in 'Improving the atomic modelling for solar UV radiative transfer calculations' submitted to MNRAS (2025). All data is level resolved and is described in the article. Photo-ionisation is not included for short-lived states, which may affect some line intensities. The only data missing compared to the models used in the article are the suppression factors for dielectronic recombination, which will not affect the continuum intensities, but is likely to alter line intensities from singly-charged and higher species. Suppression factors can be calculated from the Summers 1974 effective recombination rates given on the OPEN ADAS website, open.adas.ac.uk. The second version includes atomic models in the Lightweaver format and in an ascii format. The data are identical to those used in the paper and in the v1 Zenodo files. The ascii format is loosely based on the RH atomic data format. The units are given in the headers for each type of transition. No data is scaled except for electron impact excitation, which are the thermally-averaged collisions strengths or upsilons from Seaton (1953). For each transition the ID of each level involved follows the Lightweaver convention, that is, the ID for level j is always the upper energy level and the ID for level i is the lower energy level regardless of the direction of the transition. The f-values given in the files are not true f-values: they are the A-values from Chianti converted to an f-value using the electric dipole conversion formula. Lightweaver uses the same formula for all transitions to convert the inputted f-value to an A-value. It is the A-value that is used throughout the calculation in Lightweaver.