208
10 Hetero- and Under-Coordination Coupling
(2) Defects create both entrapment (T = 461.14 eV) and polarization states (P
= 456.41 eV) to the TiO 2 in addition to the B valley. However, the O 1s
shows only entrapment (T = 531.33 eV) without polarization. The O 1s orbit,
528.83 − 458.41 = 71.42 eV deeper than that of the TiO 2 , seems insensitive
to the polarization that screens and splits the interatomic potential acting on
oxygen.
(3) The peak intensities of the entrapment and the polarization increase with defect
concentration. The effective CN of the defected-TiO 2 is lower than that of the
ideal surface of 3.5 for the Ti(0001) skin. The ZPS gives polarization coefficient:
p =
E 2 p 3/2 (P) − E 2 p 3/2 (0)
/
E 2 p 3/2 (12(TiO 2 )) − E 2 p 3/2 (0)
= 0.71.
(4) Because the CLS is proportional to the equilibrium bond energy, one can obtain
the TiO 2 bulk bond energy E b (TiO 2 ) = 1.51 eV/bond and defected bond
energy E b (defect) = 2.11 eV/bond in comparison to that of Ti bulk bond
energy E b (Ti) = 0.41 eV/bond [21].
The valence ZPS in Fig. 10.2c shows co-existence of entrapment and polarization.
Therefore, the valence and the core band shift simultaneously in the same direction
because of the screening effect on the core charge, which are the same to Ag/Pd alloy
and Rh adatoms. The ZPS in Fig. 10.2d for different oxygen coverages matches DFT
derivatives in energy below E F . Table 10.1 summarizes the oxidation and defect effect
on the E 2p and the VB attributes of Ti and TiO 2 .
Table 10.1 Layer-order resolved E 2p 3/2 for Ti(0001), the VB for O–Ti(0001), and the defectinduced entrapment and polarization of the core and the VB for TiO 2
z
Ti(0001) E 2p 3/2
Defected TiO 2
O-adsorbed Ti(0001) [22]
m
4.6 [17]
5.34 [23, 24]
Atom
0
451.47
–
–
Bulk
12.00
453.61
458.41(B)
–
S 3
6.48
454.22
–
–
S 2
4.36
455.11
–
–
S 1
3.50
456.00
–
–
E 2p 3/2
461.14(T)
456.41(P)
–
–
O 1s
529.8(B)
531.3(T)
VB
1.0 (P)
1.6 (antibond)
4.5 (B)
−1.6 ± 0.5 (nonbond)
−1.5 ± 1.5 (hole)
8 ± 1(T)
−6.0 ± 1 (bond)
10 Hetero- and Under-Coordination Coupling
(2) Defects create both entrapment (T = 461.14 eV) and polarization states (P
= 456.41 eV) to the TiO 2 in addition to the B valley. However, the O 1s
shows only entrapment (T = 531.33 eV) without polarization. The O 1s orbit,
528.83 − 458.41 = 71.42 eV deeper than that of the TiO 2 , seems insensitive
to the polarization that screens and splits the interatomic potential acting on
oxygen.
(3) The peak intensities of the entrapment and the polarization increase with defect
concentration. The effective CN of the defected-TiO 2 is lower than that of the
ideal surface of 3.5 for the Ti(0001) skin. The ZPS gives polarization coefficient:
p =
E 2 p 3/2 (P) − E 2 p 3/2 (0)
/
E 2 p 3/2 (12(TiO 2 )) − E 2 p 3/2 (0)
= 0.71.
(4) Because the CLS is proportional to the equilibrium bond energy, one can obtain
the TiO 2 bulk bond energy E b (TiO 2 ) = 1.51 eV/bond and defected bond
energy E b (defect) = 2.11 eV/bond in comparison to that of Ti bulk bond
energy E b (Ti) = 0.41 eV/bond [21].
The valence ZPS in Fig. 10.2c shows co-existence of entrapment and polarization.
Therefore, the valence and the core band shift simultaneously in the same direction
because of the screening effect on the core charge, which are the same to Ag/Pd alloy
and Rh adatoms. The ZPS in Fig. 10.2d for different oxygen coverages matches DFT
derivatives in energy below E F . Table 10.1 summarizes the oxidation and defect effect
on the E 2p and the VB attributes of Ti and TiO 2 .
Table 10.1 Layer-order resolved E 2p 3/2 for Ti(0001), the VB for O–Ti(0001), and the defectinduced entrapment and polarization of the core and the VB for TiO 2
z
Ti(0001) E 2p 3/2
Defected TiO 2
O-adsorbed Ti(0001) [22]
m
4.6 [17]
5.34 [23, 24]
Atom
0
451.47
–
–
Bulk
12.00
453.61
458.41(B)
–
S 3
6.48
454.22
–
–
S 2
4.36
455.11
–
–
S 1
3.50
456.00
–
–
E 2p 3/2
461.14(T)
456.41(P)
–
–
O 1s
529.8(B)
531.3(T)
VB
1.0 (P)
1.6 (antibond)
4.5 (B)
−1.6 ± 0.5 (nonbond)
−1.5 ± 1.5 (hole)
8 ± 1(T)
−6.0 ± 1 (bond)