Accession Number:

ADA261792

Title:

Halogen Adlayers on Ag(111)

Descriptive Note:

Technical rept. no. 17, 30 Jun 1992-31 Mar 1993

Corporate Author:

MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE

Personal Author(s):

Report Date:

1993-03-20

Pagination or Media Count:

24.0

Abstract:

Atomically smooth halogen adlayers on Ag111 AgX, where X I, Br, Cl and F have been prepared by quenching of heated Ag samples in concentrated acid halide HX solutions. The AgX adlayers are chemically stable in air for several hours, allowing detailed characterization of the adlayer atomic structures by scanning tunneling microscopy STM. STM images of I adlayers are consistent with a nearly perfect square root of 3 x square root of 3R30 structure F, Cl and Br adlayers, however, are characterized by a parallel double row structure of adsorbed halogen atoms, oriented along the 110 direction on the Ag111 substrate. The row structure observed by STM for Cl and Br adlayers is shown to be consistent with low-energy-electron-diffraction LEED patterns, but inconsistent with the corresponding structures derived from LEED. The degree of symmetry in the various adlayers decreases with increasing adatom electronegativity, indicating that the local charge distribution around the adlayer atom, and its size, are the controlling factors in determining the adlayer structure.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry
  • Electricity and Magnetism
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE