The VUV Absorption Spectrum of Lead Monoxide.

Abstract The VUV absorption spectrum of PbO vapor down to 300 A has been observed for the first time. Four ionization energies have been determined from Rydberg series at 8.73, 8.83, 12.81, and 26.28 eV corresponding to the X 2 Π, A 2 Σ + , B 2 X + , and C 2 Σ + electronic states of the PbO + ion.