AVS 46th International Symposium
    Surface Science Division Thursday Sessions
       Session SS2-ThA

Paper SS2-ThA7
The Surface Chemistry of Iron Pentacarbonyl on Palladium (111)

Thursday, October 28, 1999, 4:00 pm, Room 607

Session: Adsorption at Surfaces
Presenter: M.N. Rocklein, University of California, Davis
Authors: M.N. Rocklein, University of California, Davis
D.P. Land, University of California, Davis
Correspondent: Click to Email
The interaction of organometallic compounds with surfaces can lead to catalytically-active surface moieties or to metal deposition. This is important to industries concerned with supported metal catalysts, magnetic storage, and microelectronics. Depending of the exposure, iron pentacarbonyl desorbs from the close-packed palladium surface in ultra-high vacuum at 153 and 170 K. This corresponds to multilayer and saturation coverage desorption. However, approximately 30% of the first saturation layer decomposes on the surface during the temperature programmed desorption (TPD) experiment. This implies that some reaction was initiated below 170 K. Laser-induced thermal desorption Fourier transform mass spectrometry (LITD-FTMS) is capable of showing time-resolved changes in molecular surface composition. Interestingly, LITD shows that submonolayer coverages react at 150 K with further decomposition near 200 K. This study represents the first LITD-FTMS temperature survey of an organometallic/substrate system. TPD further shows evolution of carbon monoxide by a reaction-limited process near 260 K. The simplest explanation of this behavior involves a stepwise decarbonylation and the existence of surface intermediates up to at least 260 K. The proposed mechanism is further supported using reflection-absorption infrared spectroscopy (RAIRS).