The magic Rydberg states of ZEKE spectroscopy

The extraordinary stability of the magic ZEKE states has been demonstrated in experiments in which a molecule is dissociated [39, 40]. For example, one can start by exciting HBr into the magic states, then pulsed- 

The precise nature of the magic Rydberg states is still a matter of controversy. It seems likely that they are states of high angular momentum, since otherwise their lifetimes (which scale as n5 rather than n3) would not be high enough. If so, then photoexcitation alone would not allow them to be reached, and it is likely that collisions with atoms of the residual vacuum play some role in populating them. 

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