Rydberg states decay behavior

This opposite branching behavior observed in the ZEKE spectrum can be explained if one considers the effect of spin-orbit autoionization. The contribution of spin-orbit autoionization to the decay by autoionization (hence loss of those molecules to the ZEKE signal) of the high-n Rydberg states, during the delay time, differently affects the intensity of the two spin-orbit components. 

From the very earliest calculations of transition frequencies, it was recognized that the inaccuracy of standard density functional approximations (LDA, GGA, hybrids) for the ground-state XC potential leads to inaccurate KS eigenvalues. Because the approximate KS potentials have incorrect asymptotic behavior (they decay exponentially, rather than as 1/r, as seen in Figure 3 and its discussion), the KS orbital eigenvalues are insufficiently negative, the ionization threshold is far too low, and the Rydberg states are often unbound. 

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