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MO: Molekülphysik

MO 41: Hauptvortr
äge

MO 41.1: Hauptvortrag

Dienstag, 8. März 2005, 10:15–10:45, HU 2091

Molecular dynamics following resonant core excitation — •Maria Novella Piancastelli — Physics Department, Uppsala University, 75 121 Uppsala, Sweden

The study of electron decay spectra in isolated atoms or molecules following a primary electronic excitation to an empty level (such as an empty molecular orbital or a Rydberg state) below a core ionization threshold provides a wealth of information on the nature of the intermediate state and on the dynamics of the whole relaxation process. These studies are very usefully complemented with absorption and absorption-type experiments such as partial and total ion yield spectroscopies.

These experimental methods have allowed us to obtain a deep insight in photoexcitation and photoionization dynamics. In particular, the phenomenon of ultrafast dissociation, i.e. molecular fragmentation taking place on the same time scale as resonant Auger decay, is nowadays possible to investigate in great detail. Several examples will be provided, including ultrafast dissociation occurring in water [1], electron Auger Doppler effect in atomic oxygen produced following ultrafast dissociation of core-excited molecular oxygen [2], and novel insight on the nature of resonant processes by ion spectroscopy [3,4.

[1] I.Hjelte, M.N.Piancastelli, R.F.Fink, O.Björneholm, M.Bässler, R.Feifel, A.Giertz, H.Wang, K.Wiesner, A.Ausmees, C.Miron, S.L.Sorensen and S.Svensson, Chem.Phys.Lett. 334, (2001) 151

[2] O.Björneholm, M.Bässler, I.Hjelte, R.Feifel, H.Wang, C.Miron, M.N.Piancastelli, S.Svensson, S.L.Sorensen, F.Gelmukhanov and H.Agren, Phys.Rev.Lett. 84, (2000) 2826

[3]W.C.Stolte, D.L.Hansen, M.N.Piancastelli, I.Dominguez Lopez, A.Rizvi, O.Hemmers, H.Wang, A.S.Schlachter, M.S.Lubell and D.W.Lindle, Phys.Rev.Lett. 86, (2001) 4504

[4] M.N.Piancastelli, W.C.Stolte, R.Guillemin, A.Wolska, S.-W.Yu, M.M.SantAnna and D.W.Lindle , J.Chem.Phys., in press