An IR diode laser spectroscopic study of adsorption and intermolecular interactions on stepped metal surfaces: CO on vicinal Cu(100). [IR (infrared)]

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:6908581

Borguet, E R

The kinetics of elementary surface processes, intermolecular interactions and stepped surfaces are intrinsic scientific interest, as well as being important to industrially relevant processes such as catalysis. A novel time-resolved surface sensitive technique. Transient Diode Laser Infrared Reflection-Absorption Spectroscopy, has been developed to investigate adsorption on stepped metal surfaces. The IR spectra display anomalous intensity behavior resulting in a minority step-CO species accounting for a disporportionate fraction of the spectral intensity. A model has been elaborated which successfully accounts for, and simulates, the observed spectra. This enables site specific concentrations to be determined, even in the presence of strong dynamic-dipole coupling. These methods allow the spectroscopy, kinetics and intermolecular interactions of CO on a stepped Cu(100) surface to be probed. In particular, it has been possible to observe a dynamic equilibrium between CO adsorbed at step and terrace sites and to investigate the kinetics of site exchanges on this surface. The IR spectra also reveal the nature and range of the intermolecular interactions and the local order which results. The CO/Cu(100) system is characterized by repulsive first and second nearest neighbor interactions. As a consequence, the adsorbates adopt a configuration which maximizes the intermolecular distance. Additionally, a non-resonant, broadband, adsorbate induced change in surface reflectivity is observed both in the IR and visible. This linear dependence of this signal with coverage provides a simple method of determining total absorbed CO concentration.

• Research Organization: Pennsylvania Univ., Philadelphia, PA (United States)
• OSTI ID: 6908581
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CARBON MONOXIDE
ADSORPTION
INTERMOLECULAR FORCES
COPPER
INFRARED SPECTRA
SURFACE PROPERTIES
LASER SPECTROSCOPY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
METALS
OXIDES
OXYGEN COMPOUNDS
SORPTION
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENTS
664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)