Resonant interlayer

The effect of such metal cluster and cluster related but also plain metal films is explained on one hand by the strong enhancement of the field strength of light due to surface plasmons and Mie plasmons (not for plain metals), which are driven by the irradiation of the cluster layer. The resonant interlayer now is driven by the plasmons, and the fluorophore is exposed to this enhanced light field of the interlayer and has consequently an enhanced absorption probability. On the other hand during emission the fluorophore acts as radiating dipole and oscillator, thereby influenced by the nearby resonant layer. Thus, an additional charge is induced and the emission process is enhanced. 

Variations in interlayer cation sites in clay minerals as studied by Cs MAS nuclear magnetic resonance spectroscopy. Am. Mineral. 75 970 (1990). ... 

Water on Smectites. Compared to vermiculites, smectites present a more difficult experimental system because of the lack of stacking order of the layers. For these materials, the traditional technique of X-ray diffraction, either using the Bragg or non-Bragg intensities, is of little use. Spectroscopic techniques, especially nuclear magnetic resonance and infrared, as well as neutron and X-ray scattering have provided detailed information about the position of the water molecules, the dynamics of the water molecule motions, and the coordination about the interlayer cations. 

Spectroscopic techniques such as electron spin resonance (ESR) offer the possibility to "probe" the chemical environment of the interlayer regions. With the ESR technique, an appropriate paramagnetic ion or molecule is allowed to penetrate the interlayer, and chemical information is deduced from the ESR spectrum. Transition metal ions, such as Cu2+, and nitroxide radical cations, such as TEMPAMINE (4-amino-2,2,6,6-tetramethylpiperidine N-oxide) have been used as probes in this manner (6-14). Since ESR is a sensitive and non-destructive method, investigations of small quantities of cations on layer silicate clays at various stages... 

Data. reported in Table 3,12 shows resistivity as an exponential function of the degree of fluo-rination. The higher the degree of fluorination the more resistance is developed CF,, is an insulator. The increase in the resistivity of fluorinated carbon is due to a loss of resonating electrons and an increase in the interlayer spacing. 

It follows from the calculations (Figs. 34 and 35) that at low frequencies, a divergence arises in the effective dielectric constant and in the effective conductivity (a sharp increase in losses). This is explained by the fact that finite clusters of the metallic phase now arise in the system which are separated by thin insulating interlayers. Such structures form a hierarchical self-similar chaotic capacitance net that generates a system of resonance frequencies. 

Fig. 2 Terahertz transmission spectra for various values of interlayer separation d. Anticrossing of the optical-like (stronger) and acoustic-like (weaker) resonances takes place at = 19.8 nm.

A and B sites can account for the 2 1 relative intensity of the two methyl resonances in the CP/MAS NMR spectra of the two phases. However, the chain packing and the interlayer spacing in the -y-form is different from that in the a-form. In the a-form, an average value of 5.13 A can be attributed to distance a, and a value of 5.34 A to distance b. In the -y-form an inversion occurs, with distance a being longer than distance b. This inversion is likely to be related to the corresponding inversion of the chemical shifts A and B in the two crystal forms. 

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