Non-linear optical studies of adsorbates: Spectroscopy and dynamics
In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5538721
- Report Number(s):
- LBL-27694; ON: DE90001543; TRN: 89-026045
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
SURFACES
NONLINEAR OPTICS
ADSORPTION
CARBON MONOXIDE
CRYSTALS
DIFFUSION
DYNAMICS
EXCITATION
GRATINGS
MOLECULES
NICKEL
SPECTROSCOPY
SURFACE PROPERTIES
VIBRATIONAL STATES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
MECHANICS
METALS
OPTICS
OXIDES
OXYGEN COMPOUNDS
SORPTION
TRANSITION ELEMENTS
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)