Welcome to TOPbase [1, 2], the Opacity Project [3] on-line atomic database.

TOPbase contains the most complete dataset of LS-coupling term energies, f-values and photoionization cross sections for astrophysical abundant ions (Z=1-26) that is currently available. They have been computed in the close-coupling approximation [4] by means of the R-matrix method [5] with innovative asymptotic techniques [6].

In most cases the accuracy of the data is comparable with that obtained by other state-of-the-art atomic physics numerical approaches. TOPbase also contains large datasets of f-values for ions of Fe with configurations 3sx3py3dz, referred to as the PLUS-data [7], computed with the atomic structure code SUPERSTRUCTURE [8]. You can either ftp the original raw files or make use of the interactive searching facilities to display custom views of: