Implications of electron correlations for multiphoton excitation

Doubly excited states of atoms display strong electron correlations, particularly with increasing excitation and in the vicinity of the double-ionization limit. We discuss the nature of these correlations and the attendant implications for multiphoton excitation of such states. Questions discussed include favored and unfavored pathways of excitation and whether multiphoton multiple ionization of atoms proceeds through a sequential ejection of the electrons or through a direct simultaneous ejection into the multielectron continuum. © 1987, Optical Society of America