nner-shell photodetachment of negative ions has been investigated using the photon-ion merged beam technique for atomic and small cluster systems. The case of atomic systems is illustrated by reporting on the first measurements of the absolute cross-sections for the formation of Pt(+), pt(2+), and Pt(3+) following 4f and 5p inner-shell photoexcitation and detachment of Pt(-) 4f(14)5d(9)6s(2) (2)D. The Pt(3+) production channel is dominated by 4f detachment and allows for the first observation of a d-wave Wigner threshold law following single-photon absorption. Our measurements show that promoting a 5p electron into the 5d orbital produces a shape resonance, while promoting a 4f electron produces Feshbach resonances, demonstrating the importance of core-valence interactions. The photodetachment of small cluster systems is illustrated with the measurement and the calculation of K-shell photodetachment of size-selected B(2)(-) and B(3)(-) clusters. The experimental absolute photodetachment cross-sections exhibit bound resonances below threshold and two shape resonances above the K-shell threshold. Similar results were obtained for all of the cationic products observed, B(+) and B(2)(+). from B(2)(-), as well as B(+), B(2)(+) and B(3)(+) from B(3)(-). The overall agreement between measured and calculated photodetachment cross-sections is very good. (C) 2010 Elsevier B.V. All rights reserved.

Shape and Feshbach resonances in inner-shell photodetachment of negative ions

TOFFOLI, DANIELE;
2011

Abstract

nner-shell photodetachment of negative ions has been investigated using the photon-ion merged beam technique for atomic and small cluster systems. The case of atomic systems is illustrated by reporting on the first measurements of the absolute cross-sections for the formation of Pt(+), pt(2+), and Pt(3+) following 4f and 5p inner-shell photoexcitation and detachment of Pt(-) 4f(14)5d(9)6s(2) (2)D. The Pt(3+) production channel is dominated by 4f detachment and allows for the first observation of a d-wave Wigner threshold law following single-photon absorption. Our measurements show that promoting a 5p electron into the 5d orbital produces a shape resonance, while promoting a 4f electron produces Feshbach resonances, demonstrating the importance of core-valence interactions. The photodetachment of small cluster systems is illustrated with the measurement and the calculation of K-shell photodetachment of size-selected B(2)(-) and B(3)(-) clusters. The experimental absolute photodetachment cross-sections exhibit bound resonances below threshold and two shape resonances above the K-shell threshold. Similar results were obtained for all of the cationic products observed, B(+) and B(2)(+). from B(2)(-), as well as B(+), B(2)(+) and B(3)(+) from B(3)(-). The overall agreement between measured and calculated photodetachment cross-sections is very good. (C) 2010 Elsevier B.V. All rights reserved.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2870436
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