Berlin 2005 – scientific programme
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MO: Molekülphysik
MO 13: He and Molecular Clusters
MO 13.3: Talk
Friday, March 4, 2005, 15:00–15:15, HU 2097
Size Dependent Spectral Shifts in Core-to-Valence Transitions of Molecular Van der Waals Clusters — •Ioana L. Bradeanu1, Roman Flesch1, Nobuhiro Kosugi2, Andrey A. Pavlychev3, and Eckart Rühl1,2 — 1Institut für Physikalische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Institute for Molecular Science, Myodaiji, Okazaki, 444-8585, Japan — 3St. Petersburg State University, St. Petersburg 198904, Russian Federation
Core-to-valence transitions of molecular clusters containing benzene and pyridine are investigated in the C 1s- and N 1s-regime ((C 1s and N 1s)→π* transitions). The vibrationally resolved bands show in clusters the same shape as in the isolated molecule, but in the case of C 1s-excited benzene clusters there is a cluster size dependent redshift relative to the bare molecule ranging between 45 meV and 65 meV. In contrast, there is a blueshift by 60 meV in N 1s-excited small pyridine clusters. The experimental results are assigned in comparison with ab initio calculations and the core-to-valence transition energies, oscillator strengths, term values, and core ionization energies of core-excited molecules and clusters are calculated using the GSCF3 package. This approach is optimized for core-excited species. It is based on the improved virtual approximation (IVO), which takes the effect of the core hole in the Hartree-Fock Hamiltonian into account. This allows us to derive an assignment of site specific spectral shifts in molecular clusters containing aromatic molecules as well as gas-to-solid shifts.