Neutral Ba 8snl (l = 6, 7) plus 5fn'l' double Rydberg spectroscopy

摘要

We present an experimental study of the Ba 8snl double-Rydberg states, using two-photon core-electron excitation from selectively prepared high-l 6snl Rydberg states (n = 12-15 and l = 6-7). The 8snl resonances recorded in the vicinity of the 6s +/- 8s two-photon ionic transition exhibit mixing with the neighboring 5f(7/2,5/2)n'l' double-Rydberg series. The increasing strength of this configuration mixing as I decreases is due to the multipole terms of the e-e Coulomb interaction expansion in the final excited state that results from polarization of the inner 8s core electron by the presence of the outer nl electron. The interpretation of the complex 8snl = 6 + 5fn'l' structures is carried out through the parametrical multichannel quantum defect theory and a Lu-Fano plot analysis. (C) 1997 Optical Society of America.