Impact-collision ion scattering spectroscopy applied to the determination of atomic surface structure
The technique of impact collision ion scattering spectroscopy (ICISS) was used to investigate the atomic structure and low energy ion scattering dynamics from various surfaces. A new formalism for calculating the three-dimensional cross section for an ion to scatter sequentially and classically from two atoms has been developed. This method can be used to assist in the interpretation of ICISS data in terms of quantitative surface-structure models. In an ICISS investigation of the Ag(110) surface, a surface flux peak analysis demonstrated that the surface was not a complete monolayer, but rather contained 10-15% random vacancies. Subsurface Li{sup {plus}} scattering results confirmed the oscillatory relaxation of the first two atomic layers of the surface, with {Delta}{sub 12} {equals} {minus}7.5% and {Delta}{sub 23} {equals} 4.0%. Modeling of the neutralization mechanism for the He{sup +} scattering gave a best fit time-dependent Auger neutralization time constant of 0.84 {+-} 0.08 fs. A neutralization study of 5 keV He{sup +} ions scattered from Au adatoms on the Si(111)-{radical}3 {times} {radical}3-Au surface showed the He{sup {plus}} ICISS data contained false shadowing features that were actually the result of local neutralization effects. A detailed examination of the Si(111)-{radical}3 {times} {radical}3-Ag surface was also made. The 5 keV Li{sup {plus}} ICISS data gave evidence for Ag island formation at single monolayer coverages of silver, while the LEED, AES and LEIS data showed that at relatively high coverages of Ag (35 ML) small areas of {radical}3 {times} {radical}3 character were still present.
- Research Organization:
- California Univ., Los Angeles, CA (United States)
- OSTI ID:
- 5461890
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
GOLD
ION COLLISIONS
HELIUM IONS
COLLISIONS
LITHIUM IONS
SILICON
SILVER
COMPARATIVE EVALUATIONS
CROSS SECTIONS
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
MATHEMATICAL MODELS
RECOMBINATION
SCATTERING
SPECTROSCOPY
SURFACES
CHARGED PARTICLES
DATA
ELEMENTS
INFORMATION
IONS
METALS
NUMERICAL DATA
SEMIMETALS
TRANSITION ELEMENTS
656003* - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-)