"Absolute cross sections for photoionization of the 6s6p ¹P excited state of barium were measured over the range 420 - 368 nm. This range includes threshold as well as numerous autoionizing resonances resulting from excitation to discrete states embedded in the ionization continuum. The experiments were motivated by a need to compare theoretically determined cross sections with experimentally determined ones for the purpose of evaluating the efficacy of the theoretical techniques employed. Moreover, discrepancies between theory and earlier experimental results were resolved by the work carried out for this dissertation. The results are now in essential agreement with the theory. The experiments were performed using an atomic beam apparatus and two lasers. One laser beam, of fixed wavelength, excited ground state barium atoms to the 6s6p ¹P state while the other, of variable wavelength, was used to ionize these atoms. Several different combinations of polarizations of the laser light were employed so that, in conjunction with angular momentum algebra, the cross sections for photoionization to specific final J-states could be determined. These state-to-state determinations are the first reported and thus test the theory at a more fundamental level than ever before"--Abstract, page iii.
Missouri University of Science and Technology
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