Studies of surfaces using optical second-harmonic generation
The experiments reported in this thesis demonstrate the use of second-harmonic generation (SHG) and sum-frequency generation (SFG) in reflection from surfaces to study various surface properties. The experiments firmly establish SHG as a viable new surface probe that complements existing surface probes in ultrahigh vacuum environments and is in many ways unique for studying interfaces between dense media. Surface structural symmetry can be revealed through the anisotropy in the SH signal from the surface as the sample is rotated about its normal. The form of this anisotropy is derived in theory and verified with an experiment on the Si(100) and (111) surfaces. The SHG and SFG signals from molecules adsorbed on noninteracting substrates have a direct relationship to the number, average orientation, and spectroscopic properties of the molecules. The SH intensity was used to measure the isotherm for adsorption of p-nitrobenzoic acid from ethanolic solution to fused silica. Experiments performed on a strongly-interacting well-characterized Rh(111) surface in ultrahigh vacuum establish the sensitivity of the SH probe in corroboration with other surface probes. For the first time, the SH coverage-dependence was fit by theory in a quantitative way for the case of O-atom adsorption. The sensitivity of SH to adsorption at different sites was established for CO on top- and bridge-sites. SHG was shown to be surface specific in that the SHG from alkali metal surfaces originates from the first two monolayers. SH sensitivity to the adsorption of catalytically-important hydrocarbons and to chemical processes such as benzene dehydrogenation was also demonstrated. 122 references, 27 figures, 2 tables.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6779249
- Report Number(s):
- LBL-17820; ON: DE84012306
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
Similar Records
Recent studies on second-harmonic generation as a surface probe
Nonlinear optical studies of molecular interaction with a silver surface
Related Subjects
GENERAL PHYSICS
36 MATERIALS SCIENCE
RHODIUM
CRYSTAL STRUCTURE
OPTICAL PROPERTIES
REFLECTIVITY
SILICON
SURFACES
DIFFRACTION
EXPERIMENTAL DATA
SYMMETRY
ULTRAHIGH VACUUM
COHERENT SCATTERING
DATA
ELEMENTS
INFORMATION
METALS
NUMERICAL DATA
PHYSICAL PROPERTIES
PLATINUM METALS
SCATTERING
SEMIMETALS
SURFACE PROPERTIES
TRANSITION ELEMENTS
640301* - Atomic
Molecular & Chemical Physics- Beams & their Reactions
360602 - Other Materials- Structure & Phase Studies