Accession Number:

ADA237466

Title:

Surface Structure and Surface Order

Descriptive Note:

Technical rept. 6 Jan 90-15 May 91,

Corporate Author:

MAINE UNIV AT ORONO LAB FOR SURFACE SCIENCE AND TECHNOLOGY

Personal Author(s):

Report Date:

1991-05-15

Pagination or Media Count:

81.0

Abstract:

This chapter provides an introduction to the current state of knowledge about the crystal structure of solid surfaces, phase transformations on surfaces, and defects on surfaces. Spatial arrangements of atoms near surfaces and interfaces determine the chemical, electronic and mechanical properties of materials. Processes such as epitaxial growth of thin films and catalytic reactions are sensitive functions of surface structure and composition. Significant gaps remain in understanding some materials and, in particular, real surfaces such as those of non-crystalline materials like polymers. Surface properties of oxides and carbides are dominated by the presence of defects and are only beginning to be understood. Real surfaces are often formed in metastable structural states rather than in thermodynamic equilibrium. With the recent introduction of direct imaging techniques like scanning tunneling microscopy STM and low energy electron microscopy LEEM, there has been a rapid increase in research directed toward understanding the noncrystalline aspects of surface structure. Surface defects range from atomic scale defects such as impurities and vacancies to macroscopic imperfections such as grain boundaries. Diffusion, nucleation, growth, and chemical reactivity are sensitive to the presence of surface defects of both mesoscopic and microscopic extent. This chapter places emphasis on surface defects.

Subject Categories:

  • Physical Chemistry
  • Crystallography
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE