Excitation plasmon

La Verne and Mozumder (1993) carefully analyzed the necessary conditions for the occurrence of plasma excitation in water and found no convincing 

More recent analysis by Fano (1992) gives a criterion for plasma excitation, which may be written as 

Various criteria for plasma resonance can be obtained by setting the dielectric function to be zero in the long-wavelength limit. Thus, in terms of t and e2, Ehrenreich and Philipps (1962) give the requirement of plasmon excitation as follows (1) x, 2 1 (2) dei /d(0 0, de2 ld(0 0 and (3) ( / t) (d /dco) 1, (g)/e) de2 dof 1. There is evidence that such conditions are met in some condensed media including group III-V semiconductors (Ehrenreich and Philipps, 1962) but not in water (LaVeme and Mozumder, 1993). 

Finally, the integral of the oscillator strength up to E = 30 eV only amounts to -3.0 in both gaseous and liquid water, which falls much shorter than the value 10 if all the electrons were to participate in plasma excitation, giving an excitation energy -21 eV 

Ashley, J. C., and Williams, M. W. (1983), Report of the Rome Air Force Development Center, Griffiss Air Force Base, Rome, N.Y. 

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Not only do the new and old surfaces produce surface plasmons in the island-growth mode, but the interlace between the growing film and the substrate is also capable of producing an interphase plasmon excitation. Typically an interphase plasmon will appear at an energy intermediate between the surface plasmons of the two phases. Its intensity will grow as the island phase grows laterally but will eventually disappear as the interface retreats below the thickening island layer. 

Shake-Up, Shake-Off, Multiplet Splitting and Plasmon Excitations... 

The term S0 k) in (6-9) is a correction for relaxation or final state effects in the emitting atom, such as the shake-up, shake-off and plasmon excitations discussed in Chapter 3. The result of these processes is that some absorbed X-ray quanta of energy hv are converted not into photoelectrons of kinetic energy hv-Eb, but into electrons with lower kinetic energy as well. 

Surface-enhanced Raman scattering (SERS) has emerged as a powerful technique for studying species adsorbed on metal films, colloidal dispersions, and working electrodes. SERS occurs when molecules are adsorbed on certain metal surfaces, where Raman intensity enhancements of ca. 105-106 may be observed. The enhancement is primarily due to plasmon excitation at the metal surface, thus the effect is limited to Cu, Ag, and Au, and a few other metals for which surface plasmons are excited by visible radiation. 

Stockli T, Bonard JM, Chatelain A (2000). Plasmon excitations in graphitic carbon spheres measured by EELS. Phys. Rev. B. 61 5751-5759. 

Mirkin CA, Jin R, Gao YC, Hao E, Metraux GS, Schatz GC (2003) Controlling Anisotropic Nanoparticle Growth Through Plasmon Excitation. Nature 425 487-490... 

G. Gerber By applying two-photon ionization spectroscopy with tunable femtosecond laser pulses we recorded the absorption through intermediate resonances in cluster sizes Na with n = 3,. 21. The fragmentation channels and decay pattern vary not only for different cluster sizes but also for different resonances corresponding to a particular size n. This variation of r and the fragmentation channels cannot be explained by collective type processes (jellium model with surface plasmon excitation) but rather require molecular structure type calculations and considerations. 

Under some simplifications associated with the symmetry of fullerenes, it has been possible to perform calculations of type Hartree-Fock in which the interelec-tronic correlation has been included up to second order Mpller-Plesset (Moller et al. 1934 Purcell 1979 Cioslowski 1995), and calculations based on the density functional (Pople et al. 1976). However, given the difficulties faced by ab initio computations when all the electrons of these large molecules are taken into account, other semiempirical methods of the Hiickel type or tight-binding (Haddon 1992) models have been developed to determine the electronic structure of C60 (Cioslowski 1995 Lin and Nori 1996) and associated properties like polarizabilities (Bonin and Kresin 1997 Rubio et al. 1993) hyperpolarizabilities (Fanti et al. 1995) plasmon excitations (Bertsch et al. 1991) etc. These semiempirical models reproduce the order of monoelectronic levels close to the Fermi level. Other more sophisticated semiempirical models, like the PPP (Pariser-Parr-Pople) (Pariser and Parr 1953 Pople 1953) obtain better quantitative results when compared with photoemission experiments (Savage 1975). 

Figure 11. SNOM and LELS. a) schematic SNOM experiment b) spectra following transmission enhancement via surface plasmon excitations, from [39] Copyright 1998 by the American Physical Society c) LELS simulation of a similar experiment for a fast (100 kV) electron.

Figure 7.4 Schematic view of plasmon excitation within metallic nanoparticle via interaction with electromagnetic field...

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