110
6 Atomic Chains, Clusters, and Nanocrystals
246
8
10
12
0.00
0.05
0.10
0.15
0.20
Relative shift
K
E M5 (3d 5/2 )
E V (5s)
E K (M5VV)
BOLS(τ =1.45, m =1)
Ag/CeO 2
(a)
0.04
0.08
0.12
0.04
0.08
0.12
5s relative shift
3d 5/2 relative shift
Ag /CeO 2
κ MV = 1.15
5
1 0
1 5
2 0
2 5
0.0
0.1
0.2
0.3
Relative Shift
K
E M5 (3d 5/2 )
E VB (5s)
E K (M5VV)
τ =1.45, m =3.82
(b)
Ag/Al 2 O 3
0.05
0.10
0.15
0.20
0.25
0.05
0.10
0.15
0.20
0.25
0.30
Ag/Al 2 O 3
κ VM =1.21
5s relative shift
3d 5/2 relativeshift
(c)
(d)
Fig. 6.7 BOLS reproduction (solid line) of the size dependence of the E 3d , E 5s , and E k (scattered
data) for Ag particles deposited on a CeO 2 [51] and b Al 2 O 3 [54] substrates. The extended Wagner
plots (c, d) correlate the relative shift of the [ 5s (K)/ 5s (12) − 1]/[ 3d (K)/ 3d (12) − 1]
= κ VM (M = 3d, V = 5s) for Ag clusters. Reprinted with permission from [18]. Copyright 2012
American Chemical Society
With the derived m and τ values, BOLS formulation resolves the size dependence
of the 3d 5/2 , the valence 5s band, and the Auger E K of Ag particles. Figure 6.7a, b
show the BOLS theoretical reproduction of the measurements and Table 6.2 features
the derivatives. Figure 6.7c, d shows the extended Wagner plots of Ag nanostructures
on CeO 2 and Al 2 O 3 substrates. The E 3d (0) and E 3d (12) derived from the XPS of clean
Ag skin (see Table 6.2) and from the APECS are consistent, which evidence that the
BOLS governing the energy shift as probed using both XPS and APECS.
Parameters m, κ VM , η VM characterize the interface reaction or skin chemical conditioning. A higher m value means that stronger chemical bond forms between the
cluster and the substrate. The κ VM describes the effect of valence recharging during
processing. The κ VM in Table 6.2 is almost independent of the shape and size of
the particle but it is sensitive to the chemical treatment. If charge transfers from one
constituent to another, the κ VM will increase, otherwise it remains unity. The η VM
∼ = 1.21/1.15 means that the strength of crystal binding to the VB(5s) level is η VM
times stronger than that to the deeper M5(3d) level. Polarization happens only to the
antibonding vacant states or to the upper edge of the valence band in this case. The
6 Atomic Chains, Clusters, and Nanocrystals
246
8
10
12
0.00
0.05
0.10
0.15
0.20
Relative shift
K
E M5 (3d 5/2 )
E V (5s)
E K (M5VV)
BOLS(τ =1.45, m =1)
Ag/CeO 2
(a)
0.04
0.08
0.12
0.04
0.08
0.12
5s relative shift
3d 5/2 relative shift
Ag /CeO 2
κ MV = 1.15
5
1 0
1 5
2 0
2 5
0.0
0.1
0.2
0.3
Relative Shift
K
E M5 (3d 5/2 )
E VB (5s)
E K (M5VV)
τ =1.45, m =3.82
(b)
Ag/Al 2 O 3
0.05
0.10
0.15
0.20
0.25
0.05
0.10
0.15
0.20
0.25
0.30
Ag/Al 2 O 3
κ VM =1.21
5s relative shift
3d 5/2 relativeshift
(c)
(d)
Fig. 6.7 BOLS reproduction (solid line) of the size dependence of the E 3d , E 5s , and E k (scattered
data) for Ag particles deposited on a CeO 2 [51] and b Al 2 O 3 [54] substrates. The extended Wagner
plots (c, d) correlate the relative shift of the [ 5s (K)/ 5s (12) − 1]/[ 3d (K)/ 3d (12) − 1]
= κ VM (M = 3d, V = 5s) for Ag clusters. Reprinted with permission from [18]. Copyright 2012
American Chemical Society
With the derived m and τ values, BOLS formulation resolves the size dependence
of the 3d 5/2 , the valence 5s band, and the Auger E K of Ag particles. Figure 6.7a, b
show the BOLS theoretical reproduction of the measurements and Table 6.2 features
the derivatives. Figure 6.7c, d shows the extended Wagner plots of Ag nanostructures
on CeO 2 and Al 2 O 3 substrates. The E 3d (0) and E 3d (12) derived from the XPS of clean
Ag skin (see Table 6.2) and from the APECS are consistent, which evidence that the
BOLS governing the energy shift as probed using both XPS and APECS.
Parameters m, κ VM , η VM characterize the interface reaction or skin chemical conditioning. A higher m value means that stronger chemical bond forms between the
cluster and the substrate. The κ VM describes the effect of valence recharging during
processing. The κ VM in Table 6.2 is almost independent of the shape and size of
the particle but it is sensitive to the chemical treatment. If charge transfers from one
constituent to another, the κ VM will increase, otherwise it remains unity. The η VM
∼ = 1.21/1.15 means that the strength of crystal binding to the VB(5s) level is η VM
times stronger than that to the deeper M5(3d) level. Polarization happens only to the
antibonding vacant states or to the upper edge of the valence band in this case. The