Hannover 2016 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 17: Electronic Spectroscopy 2
MO 17.2: Vortrag
Donnerstag, 3. März 2016, 14:45–15:00, f102
Collective excitations and their impact on plasmon-induced double photoemission from fullerenes — Michael Schüler1, Yaroslav Pavlyukh1, Paola Bolognesi2, Lorenzo Avaldi2, and •Jamal Berakdar1 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany — 2CNR-ISM, Area della Ricerca di Roma 1, CP10, 00016 Monterotondo Scalo, Italy
The correlated release of an electron pair from a sample upon absorbing one photon, called double photoemission (DPE), is a process that is particularly sensitive to the effective electron-electron interaction. As a prototypical example we consider the C60 molecule. We analyse its strongly pronounced collective many-body excitations (plasmons) using ab initio calculations based on the timedependent density-functional theory (TDDFT). Utilizing the nonnegative matrix factorization method, the individual plasmon modes are isolated and characterized by their multipolar and spatial distribution of the associated charge-density oscillations. This allows to construct a new model for the density-density response function and the effective electron-electron interaction that accurately describes typical experiments such as electron-energy loss spectroscopy (EELS). Using our model parameterization of screened interaction and further ab initio calculations, we compute the electron-pair coincidence spectrum of C60. Both theory and experiment underpin the new features arising from the dynamically screened interaction mediating the effective electron-electron interaction and thus endorse DPE as a powerful tool for tracing electron pair correlations in complex many-body systems.