High-resolution photoabsorption study of the 3d spectrum of chromium

Abstract

The 3d absorption spectrum of Cr I is discussed in relation to many-body effects in other, similar spectra. New high-resolution data for Cr I are presented which are very extensive (over 200 new transitions), and it is shown that the whole spectrum can be completely accounted for on an independent particle model with almost no violations of the spectator electron approximation, despite the potential complexity of the term structure and the proximity in energy of the 3d and 4s electrons. Interchannel interactions are also remarkably small, as is shown by an MQDT analysis. In both respects, the spectrum of Cr I differs markedly from the spectra of other elements, such as the alkaline earths, for which many-body effects are much more significant.