New Photon-Induced Triply Excited Hollow Atom States of Lithium

Autoionization of Triply Excited Rydberg Series

“…This observation applies particularly to doubly excited states while more systematic studies of triply excited states is of fairly recent origin [1][2][3][4][5]. Studies of nonradiative decays of triply excited states are still often limited to the lowest states, although recently the first observation of the Rydberg series associated with such states has been reported [6].…”

Experimental Observation and Theoretical Calculations of Rydberg Series in Hollow Lithium Atomic States

“…These considerations explain why such an extended Rydberg series was not observed in previous photoionization experiments detecting the ion yield in the Li 1 channel. They should, however, be observable in the Li 21 channel, especially between 151.66 eV (energy of the 2s 2 1 S threshold) and 152.41 eV (2s2p 3 P Li 1 threshold): In this energy region, photoion [11] and photoelectron spectrometries should give the same results if one neglects the weak direct double photoionization process. We show in the lower part of Fig.…”

“…An earlier experiment [3] measuring the yield of Li 1 ions by photoion spectrometry did not reveal such series features. In fact, the authors specifically stated [3] "that the most striking aspect of the ion spectrum is the complete absence of any identifiable Rydberg series structure." Later measurements taking advantage of the final-state selectivity of photoelectron spectroscopy [4,5] suggested, however, that some of the observed structures could be identified as first members of Rydberg series.…”

“…For future understanding an important question is whether hollow lithium states exist which can be regarded as heliumlike doubly excited Li 1 terms plus a running outer electron or is the configuration mixing so great that Rydberg states of this type are absent? An earlier experiment [3] measuring the yield of Li 1 ions by photoion spectrometry did not reveal such series features. In fact, the authors specifically stated [3] "that the most striking aspect of the ion spectrum is the complete absence of any identifiable Rydberg series structure."…”

“…Simultaneous excitation of all three electrons can create hollow lithium states of the type nᐉn 0 ᐉ 0 n 00 ᐉ 00 with n $ 2 [1][2][3][4][5]. A calculation of some low-lying hollow lithium states in hyperspherical coordinates has been recently carried out [6] as a step towards the development of a classification scheme for triply excited states, analogous to the ͑K, T͒ A radial and angular correlation quantum numbers [7,8] used to describe the doubly excited states of helium [9].…”