Dynamics of small molecules adsorbed on platinum single crystal surfaces

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5719449

Szabo, A

In this study, the electron stimulated desorption-ion angular distribution method (ESDIAD) in combination with temperature programmed desorption (TPD), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) has been used to study dynamical properties of atoms and small molecules adsorbed on single crystal surfaces. Particles desorbed in electrons stimulated desorption (ESD) often show angular distributions peaked about the directions near the chemical bond directions that were ruptured in the ESD process. Using the ESDIAD method the adsorption geometries of CO on the close packed Pt(111) and CO and NO on the stepped Pt(112) single crystal surfaces were studied. The distribution of particles desorbed in ESD about the center of the beam is related to the vibrational motion of the adsorbed particles parallel to the surface. In the present work, vibration of CO on Pt(111) and modification of the vibrational state of CO adsorbed on Pt(111) due to coadsorbed sulfur and selenium, and anisotropic vibration of NO on Pt(112) were studied. A model calculation of ESDIAD patterns quantitatively comparable to the experimental results is also presented. The desorption cross section of a given ESD product is related to the dynamics of the adsorbed and desorbing particles. In the present work isotopic substitution is used to modify the dynamics of CO adsorbed on Pt(111). With increasingly severe regulations on the composition of automotive exhaust gases, oxidation of carbon monoxide on catalytic surfaces is an increasingly important issue for the automative catalysis industry. One of the important questions concerning CO oxidation is whether the reaction is sensitive to the surface structure or not. In the present dissertation, interaction of CO(a) + O(a) on Pt single crystal surfaces was studied.

• Research Organization: Pittsburgh Univ., PA (United States)
• OSTI ID: 5719449
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330701 -- Emission Control-- Nitrogen Oxides
330702 -- Emission Control-- Carbon Monoxide
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ANGULAR DISTRIBUTION
ANISOTROPY
AUGER ELECTRON SPECTROSCOPY
BEAMS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL INDUSTRY
COHERENT SCATTERING
DESORPTION
DIFFRACTION
DISTRIBUTION
DYNAMICS
ELECTRON BEAMS
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY LEVELS
EXCITED STATES
INDUSTRY
ISOTOPIC EXCHANGE
LEPTON BEAMS
MATHEMATICAL MODELS
MECHANICS
METALS
MILLER INDICES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLE BEAMS
PLATINUM
PLATINUM METALS
SCATTERING
SELENIUM
SEMIMETALS
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SULFUR
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
VIBRATIONAL STATES