Monday, April 10, 2006, 1:00 pm — Room 300, Bldg. 555
Clusters made of simple metals like Gold or Aluminum exhibit a dramatic size dependence in their chemical reactivities. For these extremely small particles, electronic structure determines reactivity: e.g., Aun- and Agn- clusters show a pronounced even-odd alternation of O2 uptake, which can be directly related to their electron affinity /1/. Such very small particles show promising catalytic properties /2/, too, which motivates our research to gain a better understanding of the chemical properties of metal clusters.
We study the dissociation dynamics of photoinduced reactions using time-resolved photoelectron spectroscopy. Absorption of a single photon results in the desorption of an O2 molecule from a metal cluster. This process of excitation and the subsequent dissociation is recorded by a sequence of photoelectron spectra.
A second approach aims towards the chemical properties of deposited clusters. So far, the pronounced even-odd alternation of the chemical properties of the coinage metals has not been found for clusters interacting with a substrate. We studied the oxidation of size-selected Aun clusters deposited on Silicon oxide and found a low reactivity for Au5 and high reactivities for Au4 and Au6. On this substrate some of the interesting properties of free clusters seem to still be present.
/1/ B. E. Salisbury, W. T. Wallace, R. L. Whetten, Chem. Phys. 262, 131 (2000)
/2/ A. Sanchez, S. Abbet, U. Heiz, W.-D. Schneider, H. Häkkinen, R. N. Barnett, and U. Landman,
J. Phys. Chem. A 103, 9573 (1999)
Hosted by: Jim Lighstone
2944 | INT/EXT | Events Calendar
Not all computers/devices will add this event to your calendar automatically.
A calendar event file named "calendar.ics" will be placed in your downloads location. Depending on how your device/computer is configured, you may have to locate this file and double click on it to add the event to your calendar.
Event dates, times, and locations are subject to change. Event details will not be updated automatically once you add this event to your own calendar. Check the Lab's Events Calendar to ensure that you have the latest event information.