Experimental studies of dynamics at solid surfaces

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7101858

Germer, T A

Experiments were performed using photoinduced desorption (PID), thermal desorption spectroscopy (TDS), high-resolution and time-resolved electron-energy-loss spectroscopy (HREELS and TREELS), and femtosecond multiphoton photoemission spectroscopy. The thermal and photoinduced reactions of Mo(CO)[sub 6] adsorbed on Rh(100) were studied to better understand energy transfer between a photoexcited molecule and a metal surface. The Mo(CO)[sub 6] partially dissociated upon adsorption, allowing a comparison to be made between Mo(CO)[sub 6] adsorbed on the fragment-covered surface and a more ordered CO-covered surface. The energy transfer rate was found to be larger on the fragment-covered surface. The thermal reaction of hydrogen gas with oxygen adsorbed on Pt(111) was studied with TREELS between 130 and 160 K, observing the modes associated with hydroxyl adsorbed on the surface as a function of time while the sample, preadsorbed with atomic oxygen, was exposed to hydrogen gas. A model was developed whereby the reaction to form hydroxyl occurred between a molecular hydrogen precursor and oxygen at island boundaries. The photoinduced reaction of adsorbed atomic hydrogen and molecular oxygen to form hydroxyl and water on Pt(111) was studied in order to understand the reactivity of the hot oxygen atoms produced by photodissociation of molecular oxygen. A measurement was made of the cross section for NO photodesorption from Pt(111) at 90 K. A novel time-of-flight analyzer was designed and built for detection of electrons photoemitted by a femtosecond laser. This analyzer incorporates a charged-coupled device (CCD) as a detector, whereby the time resolution is obtained by accelerating the particles and sweeping them across the CCD after they have tranversed a drift region. The new spectrometer was demonstrated by observing two photon photoemission from clean and oxygen-covered Cu(111).

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• OSTI ID: 7101858
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400500* -- Photochemistry
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGE-COUPLED DEVICES
CHEMICAL REACTIONS
COPPER
DATA
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY-LOSS SPECTROSCOPY
EXPERIMENTAL DATA
INFORMATION
METALS
MOLYBDENUM
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLATINUM
PLATINUM METALS
REACTION INTERMEDIATES
SEMICONDUCTOR DEVICES
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS