Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 1: Posters Monday (Cluster, Atoms in Fields)

A 1.38: Poster

Montag, 2. April 2001, 12:30–15:00, AT3

OPTIMAL ISOTOPE-SEPARATION SELECTIVE PHOTOIONIZATION SCHEMS: SELECTIVE IONIZATION BY ELECTRIC AND LASER FIELD AND PHOTODISSOCIATION OF MOLECULES — •Sergey Ambrosov — Inst.Appl.Math.OHMI, P.O.Box 108, Odessa-9, 65009, Ukraine

We consider the optimal schemes of selective ionization method (Letokhov et al), based on the selective resonance excitation of atoms by laser radiation into states near ionization boundary and further autoionization decay of excited states under action of electric field. We present numeral data for autoionization of states for alkali atoms and autoionization resonances (AR) in complex multielectron heavy atoms (rare-earth atoms) in electric and laser field .It is predicted and reproduced an effect of giant broadening of the AR widths in the relatively weak external field. An appreciable dependence of the decay velocity at the moderately weak (100 V/cm ) electric field has been analysed. The optimal scheme presumes the compromise between the high excitation probability and high decay rate that determines the lower and upper boundaries for AR decay rate. New possibilities of the optimization for the ionization scheme with account of these effects are indicated. The optimal schemes for the multistage photo-dissociation of molecules under excitation through intermediate vibrationally excited state are studied. The isotope-selective vibration levels excitation scheme for molecules is also considered. QED approach to multi-photon dissociation in the IR field is proposed.