Absorption spectrum of the laser-populated ³D metastable levels in barium

The paper deals with the details of the absorption spectrum of the ³D metastable term in barium. The ³D term was selectively populated with a tuneable dye laser. The fundamental triplet series (6s5d³D-6snf³F) is identified and extended out to n=32. In addition, the absolute photoionization cross section was measured at 303 nm and found to be (18+or-4)*10^-18cm². The relative cross section from 303 to 250 nm was also measured with the absolute scale set by the measurement at 303 nm and was found to be nearly constant in the wavelength region measured.