PHOTOIONIZATION OF ATOMIC BISMUTH

The vacuum ultraviolet photoionization spectrum of atomic bismuth, covering the region from ionization threshold to 740 Angstrom, is reported. Comparison with prior photographic absorption studies from threshold to similar to 1320 Angstrom (encompassing the P-3(0)-P-3(2) energies of Bi+) indicates saturation of intense autoionization features in the densitometer traces. Although fluorescence has been observed corresponding to many of these peaks, their widths imply that autoionization is dominant. Consequently, estimates of the oscillator strengths can be made from the photoionization spectrum. The peak widths and profiles differ from those in arsenic and antimony, probably due to significant departure from LS coupling. New series are observed, involving excitation of the inner valence 6s orbital, and converging to Bi+, S-5(2). They are interpreted with the aid of relativistic ab initio calculations.