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An unexpected packing of fluorinated [ital n]-alkane thiols on Au(111): A combined atomic force microscopy and x-ray diffraction study

Journal Article · · Journal of Chemical Physics; (United States)
DOI:https://doi.org/10.1063/1.467479· OSTI ID:7071034
 [1];  [2];  [3];  [4];  [2];  [4]
  1. Material Science Division and Department of Chemistry, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
  2. Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)
  3. Department of Chemistry, Stanford University, Stanford, California 94305 (United States)
  4. Material Science Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

Atomic force microscopy (AFM) and grazing incidence x-ray diffraction (GIXD) have been used to study the structure of self-assembled monolayers of CF[sub 3](CF[sub 2])[sub [ital n]](CH[sub 2])[sub 2]SH ([ital n]=11, 7, and 5) on the Au(111) surface. Surprisingly, although the nearest-neighbor fluorinated alkane thiol distance is very close to the lattice constant of a commensurate [ital p](2[times]2) structure, the close-packed rows of molecules are rotated [similar to]30[degree] with respect to the underlying gold lattice. That packing is incommensurate or at most only close to the high-order commensurate [ital c](7[times]7) structure. The relative orientation of the organic monolayer and the Au(111) substrate has been determined unambiguously both with GIXD, and by AFM, taking advantage of an earlier finding (Ref. ) that AFM tips can reversibly displace the thiol molecules under high loads. In addition, we demonstrate that the two techniques provide complementary information on the order and the domain structures of these monolayers.

DOE Contract Number:
AC03-76SF00098; AC02-76CH00016
OSTI ID:
7071034
Journal Information:
Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:5; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English