title: Binding Energy and Dissociation Barrier: Experimental Determination of the Key Parameters of the Potential Energy Curve of Diethyl Ether on Si(001).
abstract: The key parameters of the potential energy curve of organic molecules on semiconductor surfaces, binding energy of the intermediate state and dissociation barrier, were experimentally investigated for the model system of diethyl ether (Et2O) on Si(001). Et2O adsorbs via a datively bonded intermediate from which it converts via ether cleavage into a covalently attached final state. This thermally activated conversion into the final state was followed in real-time by means of optical second-harmonic generation (SHG) at different temperatures and the associated energy barrier ϵa = 0.38 ± 0.05 eV and pre-exponential factor νa = 10(4±1) s(-1) were determined. From molecular beam experiments on the initial sticking probability, the difference between the desorption energy ϵd and ϵa was extracted and thus the binding energy of the intermediate state was determined (0.62 ± 0.08 eV). The results are discussed in terms of general chemical trends as well as with respect to a wider applicability on adsorbate reactions on semiconductor surfaces.
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Reutzel
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Lipponer
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany.|Institut für Angewandte Physik, Justus-Liebig-Universität Giessen , D-35392 Giessen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Dürr
authors.affiliation: Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität , D-35032 Marburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Höfer
keywords: diethyl ether; molecular beam; potential energy curve; real-time monitoring; second-harmonic generation; silicon surface; surface reaction