Berlin 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 22: Ultrafast Surface Dynamics
O 22.6: Vortrag
Dienstag, 17. März 2015, 12:00–12:15, MA 042
Experimental determination of the potential energy curve of diethyl ether on Si(001) — Marcel Reutzel1, Marcus Lipponer1, •Michael Dürr1,2, and Ulrich Höfer1 — 1Philipps University, 35037 Marburg — 2Justus Liebig University, 34392 Giessen
The adsorption dynamics of organic molecules on semiconductor surfaces is in most cases controlled by a precursor or intermediate state. For molecules containing a heteroatom such as nitrogen or oxygen, this intermediate state involves lone pair electrons of the heteroatom and, in the case of Si(001), the empty dangling bond of the lower silicon atom. Most recently, we have shown that in the case of ether molecules one can isolate this datively bonded intermediate at low temperatures; at elevated temperatures cleavage of the O-C bond of the otherwise inert ether group was observed [1].
Here we show that, using optical second harmonic generation, we can follow in situ the conversion of diethyl ether from the intermediate to the final adsorption configuration. Measuring the kinetics as a function of surface temperature allows us to determine the associated energy barrier. Complementary information is obtained from sticking probabilities measured by means of molecular beam experiments. The dependence of the initial sticking probability on surface temperature reveals the energy difference between the conversion and desorption barrier out of the datively bonded intermediate state. Combination of the two results give full information on the potential energy curve for the adsorpton of diethyl ether on Si(001).
[1] G. Mette, et al., ChemPhysChem 15, 3725 (2014).