Main Content

2015

• Inhalt ausklappen Inhalt einklappen M. Reutzel, M. A. Lipponer, M. Dürr, and U. Höfer, Binding energy and dissociation barrier: experimental determination of the key parameters of the potential energy curve of diethyl ether on Si(001), The Journal Physical Chemistry Letters 6, 3971-3975 (2015).

  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. 

  DOI: 10.1021/acs.jpclett.5b01510

• Inhalt ausklappen Inhalt einklappen M. Reutzel, G. Mette, P. Stromberger, U. Koert, M. Dürr, and U. Höfer, Dissociative adsorption of diethyl ether on Si(001) studied by means of scanning tunneling microscopy and photoelectron spectroscopy, The Journal Physical Chemistry C 119, 6018-6023 (2015).

  The adsorption of diethyl ether (Et2O) on Si(001) was studied by means of scanning tunneling microscopy (STM) and photoelectron spectroscopy. Et2O reacts on Si(001) via a datively bonded intermediate, which was isolated at surface temperatures below 100 K. At higher surface temperature, Et2O converts dissociatively into the final state by cleaving one O–C bond; the resulting −O–C2H5 and −C2H5 fragments are found to attach on two Si dimers of neighboring dimer rows. Tip-induced hopping of the −C2H5 fragment on one dimer was observed at positive sample bias. The results are discussed in the context of recent experiments on the reaction of tetrahydrofuran (THF) on Si(001) (Mette et al. ChemPhysChem 2014, 15, 3725) and allow a more general description of the reaction of ethers on Si(001).

  DOI: 10.1021/JP511780P