Düsseldorf 2007 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 14: Molecular Clusters

MO 14.4: Vortrag

Montag, 19. März 2007, 17:15–17:30, 6D

Orbital-Dependent Stabilization in the Ionization of CS₂ Cluster — •Jürgen Plenge¹, Takaki Hatsui², Nobuhiro Kosugi², and Eckart Rühl¹ — ¹Physikalische und Theoretische Chemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin — ²Institute for Molecular Science, Myodaiji, Okazaki, 444-8585, Japan

Molecular van der Waals clusters offer the opportunity to study the gap between the isolated molecule and condensed matter. It is known that the formation of clusters leads to a decrease in the ionization energy with respect to the molecule, which is commonly interpreted in terms of final state polarization due to the created hole. In the case of valence ionization of molecular clusters, the created holes are generally delocalized within the molecule, where the shape of the hole is characteristic for the molecular valence orbital.

We present results on molecular orbital dependent stabilization of valence-ionized states in CS₂ clusters. Valence photoelectron spectra of isolated CS₂ molecules and CS₂ clusters are measured using synchrotron radiation (UVSOR-II, beamline BL3U) and a He-I discharge lamp. The experimental spectra indicate a shift of the molecular photoelectron bands in the cluster between 0.55 eV (ground state) and 0.70 eV (C state) to lower binding energy. These results are compared to results on CO₂ clusters and they are discussed in terms of a molecular orbital dependent stabilization of the final ionic states in molecular clusters, where ionized states with the lower binding energies are found to show a smaller stabilization effect.