Auto-ionizing state

A.K. Bhatia, A. Temkin, J.F. Perkins, Hylleraas variational calculation of auto-ionization states, Phys. Rev. 153 (1967) 177. 

The mechanism oftheprocess is similarto the dissociative recombination(Section2.2.2) and proceeds by intermediate formation of an auto-ionization state (AB ). This excited state is unstable and decays, leading either to the reverse reaction of anto-detachment... 

This process proceeds by the two-stage Bloch-Bradbury mechanism (Bloch Bradbury, 1935 Alexandrov, 1981) starting with the formation of a negative ion (rate coefficient att) in an unstable auto-ionization state (r is the time of collisionless detachment) ... 

The long-lifetime resonances (e.g., low energy resonances in02, NO, CeHe, etc.) correspond to auto-ionization states AB (Vj) with much longer lifetime (t = 10 " -10 s). 

Several theoretical works investigating population transfer via a continuum have been reported. In the earliest model [238], the continuum was treated as a Bixon-Jortner-type [235] unbounded set of equally spaced quasibound states. In such a model complete population transfer was shown to be possible [238]. Soon thereafter it was however pointed out [239] that complete population transfer via a true continuum is not generally achievable. Several works have tried to maximize the transfer efficiency, by employing structured continua auto-ionizing states [240] or in the case of LICS by controlling the Stark shifts, the area of laser pulses, and the effect of... 

L. Lipsky, A. Russek, Auto-ionizing states in Helium, Phys. Rev. 142 (1966) 59. 

This blockage of the process can often be avoided for elements with more than one valence electron, by tuning the ionization laser to an auto-ionizing state, which decays rapidly within its lifetime of far less than 1 ns into an ion and a free electron. This is particularly effective for lanthanide and actinide elements, which have a high density of auto-ionizing states near the... 

Compared to atomic auto-ionizing states, where lifetimes below 10"12 s are common, the molecular levels exhibit a much weaker coupling to the ionization continuum. The reason is that the molecular ionization process takes place through a coupling between nuclear motion and electronic configurations, whereas in atoms a direct electronic coupling of the excited electron to the continuum makes the auto-ionization probability by far larger. 

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