16.1 Uniqueness of Solution
321
integrated information about the bond geometry, surface topography and the DOS in
the valence band.
16.2 VLEED Capacity and Reliability
16.2.1 Decoding Procedures
Calculations were performed with the Cu 3 O 2 pairing tetrahedron structure [6] and
the optimized SPB parameters. Geometric variables required in calculations are converted from the Cu 3 O 2 bond geometry. Table 16.2 shows that any variation of the bond
geometry resulted in a collective dislocation of the surface atoms and the interface
spacing.
As references for the sensitivity examination, two I-E curves were simulated with
the z 0 -optimizing method [7]. Table 16.2 lists the optimal structure parameters and
Fig. 16.4 shows the optimized z 0 (E) profiles. Figures 16.5, 16.6, 16.7 duplicated the
measured spectra in broken curves.
VLEED spectral sensitivity was examined by letting the code read in the initial
optimal data in Table 16.2 (denoted *a and *b) and the z 0 (E) profiles in Fig. 16.4, and
then repeat the calculation by adjusting the individual parameters to be examined.
16.2.2 Sensitivity to the Bond Geometry
Figure 16.5 shows the calculation results obtained by varying the Cu 3 O 2 bond geometry. Besides the two bond parameters, BA12 and DCu x , Q 2 was treated as an additional
variable. For comparison purpose the effect of individual atomic displacement, DCu z
(denoted as D) was also examined. The structural sensitivity examination results in
Fig. 16.5 revealed the following [10]:
(1) Adjusting the bond angle BA12 and the bond contraction coefficient Q 2 modulated the D 12 spacing, which governs the fine-structure features between 7.0
and 11.0 eV, matching the spectral features collected at oxygen exposures of
25–200 L [10].
(2) Increasing DCu x attenuates the general intensity at energies below the second band-gap (<12.0 eV). This trend agrees remarkably well with the spectral
features for oxygen exposures >200 L and long term aging (>30 min) [10].
(3) Changing DCu z causes nothing more than a slight change in intensity between
9.5 and 11.5 eV, without any matching to spectral measurements. This observation supports that the single atomic-shift is less realistic than the bond-geometry
in describing the reaction dynamics.
321
integrated information about the bond geometry, surface topography and the DOS in
the valence band.
16.2 VLEED Capacity and Reliability
16.2.1 Decoding Procedures
Calculations were performed with the Cu 3 O 2 pairing tetrahedron structure [6] and
the optimized SPB parameters. Geometric variables required in calculations are converted from the Cu 3 O 2 bond geometry. Table 16.2 shows that any variation of the bond
geometry resulted in a collective dislocation of the surface atoms and the interface
spacing.
As references for the sensitivity examination, two I-E curves were simulated with
the z 0 -optimizing method [7]. Table 16.2 lists the optimal structure parameters and
Fig. 16.4 shows the optimized z 0 (E) profiles. Figures 16.5, 16.6, 16.7 duplicated the
measured spectra in broken curves.
VLEED spectral sensitivity was examined by letting the code read in the initial
optimal data in Table 16.2 (denoted *a and *b) and the z 0 (E) profiles in Fig. 16.4, and
then repeat the calculation by adjusting the individual parameters to be examined.
16.2.2 Sensitivity to the Bond Geometry
Figure 16.5 shows the calculation results obtained by varying the Cu 3 O 2 bond geometry. Besides the two bond parameters, BA12 and DCu x , Q 2 was treated as an additional
variable. For comparison purpose the effect of individual atomic displacement, DCu z
(denoted as D) was also examined. The structural sensitivity examination results in
Fig. 16.5 revealed the following [10]:
(1) Adjusting the bond angle BA12 and the bond contraction coefficient Q 2 modulated the D 12 spacing, which governs the fine-structure features between 7.0
and 11.0 eV, matching the spectral features collected at oxygen exposures of
25–200 L [10].
(2) Increasing DCu x attenuates the general intensity at energies below the second band-gap (<12.0 eV). This trend agrees remarkably well with the spectral
features for oxygen exposures >200 L and long term aging (>30 min) [10].
(3) Changing DCu z causes nothing more than a slight change in intensity between
9.5 and 11.5 eV, without any matching to spectral measurements. This observation supports that the single atomic-shift is less realistic than the bond-geometry
in describing the reaction dynamics.