MEASUREMENTS OF ABSOLUTE PHOTOIONIZATION CROSS-SECTIONS OF THE EXCITED 7D AND 8D STATES OF CESIUM

We have carried out measurements of absolute photoionization cross sec tions of the excited nd(2)D(3/2,5/2) states of cesium for principal qu antum number n = 7 and 8. Absolute cross sections have been determined experimentally using the technique of measuring depletion in the fluo rescence signal from the excited states of atoms due to photoionizatio n. The measurement was made with a linearly polarized ionization laser light at 532-nm wavelength. Photoionization cross sections have been determined as (3.5 +/- 1.4) x 10(-18) cm(2) and (3.1 +/- 1.2) x 10(-18 ) cm(2) for the 7d(2)D(3/2) and 7d(2)D(5/2), states, and (2.4 +/- 1.0) x 10(-18) cm(2) and (1.6 +/- 0.6) x 10(-18) cm(2) for the 8d(2)D(3/2) , and 8d(2)D(5/2) states, respectively. We also propose an alternative method to measure the absolute cross sections for photoionization fro m highly excited Rydberg states, which is based on the methodology of the fluorescence depletion technique. [S1050-2947(97)06011-3].