Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)
O 55.51: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
Enhancement of photodesorption by vibrational excitation — •Tijo Vazhappilly1, Stephanie Beyvers1, Tillmann Klamroth1, Rigoberto Hernandez2, and Peter Saalfrank1 — 1Institut für Chemie, Universität Potsdam, D-14476 Potsdam, Germany — 2School of Chemistry and Biochemistry, Georgia Institute of Technology,Atlanta, GA 30332-0400
The effect of selective excitation of adsorbate vibrations by tailored IR laser pulses, on the photodesorption of H2 and D2 from a Ru(0001) surface has been investigated theoretically. A two-dimensional model is used for the Desorption Induced by Electronic Transitions (DIET) limit. A jumping wavepacket algorithm is employed with different initial states, starting from ground vibrational state to vibrationally excited states and vibrational wavepackets[1]. This model is extended to Desorption Induced by Multiple Electronic Transitions (DIMET) by incorporating electronic temperatures from femtosecond UV/vis laser excitation of metal electrons. In this regime, the IR+UV/vis strategy to control the photodesorption is realized by the Monte Carlo Wave Packet (MCWP) method [2], and Molecular Dynamics (MD) with electronic friction. Vibrational preexcitation appears to be successful in both DIET and DIMET.
References: [1] T. Vazhappilly, S. Beyvers, T. Klamroth, M. Luppi, and P. Saalfrank, Chem. Phys. 338, 299 (2007). [2] P. Saalfrank, T. Vazhappilly, S. Beyvers, G.K. Paramonov, and T. Klamroth, Surf. Sci. (submitted).