of [Si]{} or to a resonance feature in the photoionisation cross section [@artru+lanz87-1; @lanzetal96-1]. We have tested such a hypothetical line with their data for the oscillator strength and line width data. However, the width ($\approx
80$Å) is much too broad to lead to visible features in the spectrum. We have also included the [Si]{} photoionisation cross sections from the Opacity Project [@seatonetal94-1], which indeed show a resonance maximum in this spectral region. But again, the Si abundance is too small to let this feature show up in the spectrum.

Our model uses the six [Si]{} lines at 1403.8, 1404.2, 1404.5, 1409.1, 1409.9, and 1410.2 Å in this range (Table\[t-idlines\]). The first two have the source “guess” in VALD, the first three have no entry in NIST, and the $\log$ gf values of the strongest line (1410.2Å) differ by $\approx 0.8$dex between the two databases. The upper levels of the transitions have a parent configuration belonging to the second ionisation limit of [Si]{}. They are still $\approx0.7$eV below the first ionisation limit and thus not strictly auto-ionising. However, the broadening may well be underestimated by our simple approximation formulae. In summary, the atomic data of the lines in the region 