Plasmons, surface

Collective excitations of conduction electrons localized near the conductor surface are called surface plasmons. In the nonretarded limit (c oo) or, equiv- 

2) An exception is the case of a 2D lattice of adsorbed atoms or molecules. 

It can be described by a wave-like form on both sides of the surface  

From here one finds the electric field amplitudes parallel to the surface  

Finally, the continuity of the E-vector tangential component and the D-vector normal component across the surface leads to the equations 

---

There are a few other surface-sensitive characterization techniques that also rely on the use of lasers. For instance surface-plasmon resonance (SPR) measurements have been used to follow changes in surface optical properties as a fiinction of time as the sample is modified by, for instance, adsorption processes [ ]. SPR has proven usefiil to image adsorption patterns on surfaces as well [59]. 

Klar T ef a/1998 Surface-plasmon resonances in single metallic nanoparticles Phys. Rev. Lett. 80 4249... 

Bulk and surface imprinting strategies are straightforward tools to generate artificial antibodies. Combined with transducers such as QCM (quartz crystal microbalance), SAW (surface acoustic wave resonator), IDC (interdigital capacitor) or SPR (surface plasmon resonator) they yield powerful chemical sensors for a very broad range of analytes. 

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. 

Sometimes it is possible to distinguish surface and bulk plasmons by lowering Eq so that the bulk plasmon will decrease in intensity more rapidly than the surface plasmon. However both surface states and interband transitions can show the same behavior. 

J. Ghijsen. Surf Sci. 126, 177, 1983. REELS spectra of pure Mg versus primary beam energy showing relative intensities of the bulk and surface plasmons. 

P. Braun. Surf. Sci. 126,714,1983. VEELS study of bulk and surface plasmon energies across Al—Mg alloy phase diagram. 

Surface plasmon resonance (SPR) Interaction strength (molar dissociation constant, K ). One member of the reacting pair needs to be immobilised onto an inert surface. Not suitable for selfassociation analysis. [7]... 

Hartmann T, Ober D (2000) Biosynthesis and Metabolism of Pyrrolizidine Alkaloids in Plants and Specialized Insect Herbivores. 209. 207-243 Haseley SR, Kamerling JP, Vliegenthart JFG (2002) Unravelling Carbohydrate Interactions with Biosensors Using Surface Plasmon Resonance (SPR) Detection. 218 93-114... 

CuNPs) in Fig. 7 shows the monodisperse and uniformly distributed spherical particles of 10+5 nm diameter. The solution containing nanoparticles of silver was found to be transparent and stable for 6 months with no significant change in the surface plasmon and average particle size. However, in the absence of starch, the nanoparticles formed were observed to be immediately aggregated into black precipitate. The hydroxyl groups of the starch polymer act as passivation contacts for the stabilization of the metallic nanoparticles in the aqueous solution. The method can be extended for synthesis of various other metallic and bimetallic particles as well. 

Homola, J., "Thin Films Study by Means of Optically Excited Surface Plasmons, Nano 94—International Coirference on Nanometrology Scanning Probe Microscopy and Related Techniques, Proceedings, Nano 94, Bmo, Czech Rep., 1994, pp. 84-87. 

More recently, the method of scanning near-field optical microscopy (SNOM) has been applied to LB films of phospholipids and has revealed submicron-domain structures [55-59]. The method involves scanning a fiber-optic tip over a surface in much the same way an AFM tip is scanned over a surface. In principle, other optical experiments could be combined with the SNOM, snch as resonance energy transfer, time-resolved flnorescence, and surface plasmon resonance. It is likely that spectroscopic investigation of snbmicron domains in LB films nsing these principles will be pnrsned extensively. 

To determine if the resonance peak is due to self-organization, optical spectra of disorganized nanocrystals (see TEM pattern inset Fig. 8) are recorded under v- and p-polar-ization. Under v-polarization, the optical spectrum obtained at 0 = 60° (Fig. 8A) shows one resonance peak at 2.7 eV. This is attributed to the surface plasmon parallel to the substrate. 

---