4 Insights into Hot Electron Properties
A significant benefit of the FD approach is the added chemical intuition derived
from expressing the electronic excitation as a linear combination of orbital excitations in the silver atomic orbital basis. Figure 9 is an energy level diagram that
shows that for the Ag 84 cluster, the plasmon peak found at 2.98 eV is made up of 15
-2
0
2
4
6
8
10
12
14
0
1
2
3
4
5
6
Absorption Cross Section (Angstrom
2
)
Energy (eV)
Fig. 7 Optical absorption spectra of Ag 35
−5 (solid) and Ag 35
+1 (dashed) using RT-TDDFT and the
PBE XC functional and PBE optimized basis set. Ag 35
−5 has a closed shell electronic structure Ag 35
+1
does not
70
60
50
40
30
20
10
0
0
50
100
150
200
250
300
350
-10
E-E f (eV)
Number of States
Fig. 8 Contribution of orbitals from the outer shell Ag atoms (solid black) and the inner core Ag
atoms (hatch marks) for Ag 120 . The shell atoms contribute most to the excited states closest to the
fermi level. Inset The shell atoms (light gray) are distinguished from the inner core atoms (dark
gray) in the Ag 120 cluster in the inset
48
L.R. Madison et al.