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Title: On the consistency of QCBED structure factor measurements for TiO2 (Rutile)

The same Bragg reflection in TiO2 from twelve different CBED patterns (from different crystals, orientations and thicknesses) are analysed quantitatively in order to evaluate the consistency of the QCBED method for bond-charge mapping. The standard deviation in the resulting distribution of derived X-ray structure factors is found to be an order of magnitude smaller than that in conventional X-ray work, and the standard error (0.026% for FX(110)) is slightly better than obtained by the X-ray Pendellosung method applied to silicon. This is sufficiently accuracy to distinguish between atomic, covalent and ionic models of bonding. We describe the importance of extracting experimental parameters from CCD camera characterization, and of surface oxidation and crystal shape. Thus, the current experiments show that the QCBED method is now a robust and powerful tool for low order structure factor measurement, which does not suffer from the large extinction (multiple scattering) errors which occur in inorganic X-ray crystallography, and may be applied to nanocrystals. Our results will be used to understand the role of d electrons in the chemical bonding of TiO2.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Arizona State Univ., Tempe, AZ (United States)
  2. Univ. of Illinois, Urbana, IL (United States)
  3. Arizona State Univ., Tempe, AZ (United States); Norwegian Univ. of Science and Technology, Trondheim (Norway)
Publication Date:
OSTI Identifier:
1164063
Grant/Contract Number:
FG03-02ER45996
Type:
Accepted Manuscript
Journal Name:
Microscopy and Microanalysis
Additional Journal Information:
Journal Volume: 9; Journal Issue: 05; Journal ID: ISSN 1431-9276
Publisher:
Microscopy Society of America (MSA)
Research Org:
Arizona State Univ., Tempe, AZ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE electron diffraction; CBED; structure factor; rutile