Interface plasmon

The ficos peak is ascribed to an interface plasmon. Assuming that the aluminium conduction electrons are well described by a free-electron gas, the interface plasmon frequency is related to the relative dielectric constant e of the molecular film through the relation ... 

One-electron wave function Ae-electron wave function cos Interface plasmon frequency... 

EELS study of this interface was carried out by Batson [5], It revealed the presence of Si2+ (SiO like layer) and possible defect states at the boundary (Figure 2a). LELS can also give information about the interface. We showed that the use of relativistic formula was essential to explain the shift of the interface plasmon peak (IPP) as the probe was moved away from the interface (Figure 2b). The agreement with the experiment allowed us to conclude that a 1 nm thick SiO layer had to be introduced between Si and Si02 to fit the IPP position precisely [6],... 

IPPs are modified by the presence of a second interface, even tens of nanometers apart. The position of the Double Interface Plasmon Peak depends essentially on the distance between the two interfaces and is not shifted as the probe position is changed (Figure 3b), contrary to the single interface case. The 0.5 eV difference between experiment and theory in the peak position for abrupt interfaces is compatible with the existence of a SiO thin layer on each interface. More details will be given elsewhere [11]. Other studies have also been performed recently on grain boundaries [12, 13] and dislocations [14], helping to choose between various possible structures. 

Several distinct energy loss peaks appear within the MgO band gap (between 1 and 5.5eV energy loss [218]) as a function of cluster size. These loss peaks cannot be assigned to low-lying transitions in the atom or in the ion [103,208,219,220]. EEL spectra of vapor deposited Ag, which forms islands and thin films via surface diffusion at sample temperatures between T = 100 and 500 K, have shown losses at 3.8 and 3.2 eV attributed to an Ag surface plasmon and to an Ag-MgO interface plasmon, respectively [218]. In contrast, the EEL spectra shown in Fig. 1.44 and recorded at T = 45K exhibit clearly a size dependence, which reflects the change in the electronic structure of the clusters. A similar behavior has been observed in optical absorption spectra of Ag (n < 21) clusters deposited in rare gas matrices [221], which has been interpreted as a manifestation of collective excitations (Mie plasmons) of the s electrons influenced by the ellipsoidal shape of the clusters. Some similarities but also some differences in the general trend with cluster size have been observed by comparing the optical absorption data shown in [221] with these EELS data [214]. In this context, it is important to note that EELS probes... 

Cohen, G., Pogreh, R., Tarahia, M., Davidov, D., and Keller, P., Interface plasmon polariton and X-ray reflectivity of ultrathin films of ferroelectric main-chain liquid crystal polymers, Ferwelectrics, 181, 227-240 (1996). 

Vijh, A.K. (1986) Electrode-potentials and interface plasmons in metal gaseous electrolyte (i.e. plasma) interphase region. Materials Chemistry and Physics, 14, 47-56. 

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. 

Ina similarmarmerto surface-enhanced Raman scattering, surface-enhancement of hyper-Raman scattering is a promising method to study adsorbed molecules on metal surfaces [24]. Based on recent developments in plasmonics, design and fabrication of metal substrates with high enhancement activities is now becoming possible [21]. Combination of the surface enhancement with the electronic resonances would also be helpful for the practical use of hyper-Raman spectroscopy. Development of enhanced hyper-Raman spectroscopy is awaited for the study of solid/liquid interfaces. 

The affinity (interaction strength), multiple interactions, and the changes in concentration can be also monitored from those studies. To deliver data in real time, the natural phenomenon of surface plasmon resonance (SPR) is employed. Since the refractive index (r ) at the interface changes as molecules are immobilized on the sensor surface, instant measure of r provides real-time assessment. The Tlcxchip platform exploits grating-coupled SPR (GC-SPR) for this purpose. 

Electromagnetic field of a surface plasmon is confined at the metal-dielectric interface and decreases exponentially into both media, Figure 6. 

Figure 5. Normalized propagation constant as a function of angular frequency for a surface plasmon propagating along gold-air interface.

Figure 6. Distribution of the magnetic field intensity for a surface plasmon at the interface between gold and dielectric with a refractive index of 1.32 for two different wavelengths.

Figure 2. Regular reflectance Replication of Snellius law for reflected and refracted radiation at interface in dependence on the refractive indices of the media adjacent to this interface, demonstrating total internal reflectance and evanescent field, exciting fluorophores close to the waveguide or even surface plasmon resonance.

Since the confined modes (whether they are waveguide modes or surface plasmons) are nonradiative (i.e., their wavevector parallel to the interface, is greater than the wavevector of the... 

Surface plasmon-polaritons (SPP), also referred as to surface plasma waves, are special modes of electromagnetic field which can exist at the interface between a dielectric and a metal that behaves like a nearly-iree electron plasma. A surface plasmon is a transverse-magnetic mode (magnetic vector is perpendicular to the direction of propagation of the wave and parallel to the plane of interface) and is characterized by its propagation constant and field distribution. The propagation constant, P can be expressed as follows ... 

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