Piezo-spectroscopic

Munisso, M.C., Yano, S., Zhu, W.L., and Pezzotti, G. (2008) Spatially resolved piezo-spectroscopic characterization for the validation of theoretical models of notch-root fields in ceramics. Continuum Mech. Thermodyn., 20 (3), 123—132. 

One of the difficulties of a quantitative analysis of scale failure is the determination of the stress state in the scalers it results from the oxide growth process and from additional substrate deformations. The application of X-ray diffraction provides usually only a limited lateral spatial resolution. For alumina scales consisting of the a-Al20, phase, Lipkin and Clarke [20] have shown recently that stresses can be measured at RT also by means of optical fluorescence spectroscopy (OFS) employing the piezo-spectroscopic effect [21]. This method permits a high spatial resolution of stress measurements in the micrometre region and is therefore especially useful for the analysis... 

Chromium impurities in the a-alumina phase fluoresce under laser irradiation of appropriate wavelength. For materials exhibiting the piezo-spectroscopic effect, the wave number, v, of the fluorescence line depends on the stress state. In the case of alumina, the line shift, Av, is approximately proportional to the stress for stresses up to a few GPa... 

Within a coordinate system suitably matched to the crystallographic directions of alumina, the non-orthogonal piezo-spectroscopic coefficients vanish (Fly = 0 for i + j). 

For the case of interconnect line features patterned on a single crystal Si substrate, a common procedure for the use of micro-Raman spectroscopy entails determination of the stress in the interconnect from the distortion produced in the substrate and the dielectric which immediately surround the interconnect (DeWolf et al. (1992) Ma et al. (1995) DeWolf et al. (1999)) the Raman spectra can be measured in the backscattering mode using an argon laser. The piezo-spectroscopic shift in the Raman spectrum, which is induced by such local distortions, can be measured to a spatial resolution on the order of 1 pan. so that stress in individual lines can be estimated. 

Fig. 3.21. Schematic showing an experimental setup for determining the piezo-spectroscopic shifts in the Raman spectrum in a Si substrate immediately surrounding an interconnect line.

Pezzotti, G. (2005) Raman piezo-spectroscopic analysis of natural and synthetic biomaterials. Anal Bioanal. Chem., 381 (3), 577 - 590. 

The conformational mobility of a chromophoric main-chain polymer is often connected to its electronic structure. Therefore, changes in the UV-visible absorption spectra and/or chiroptical properties are spectroscopically observable as thermo-, solvato-, piezo-, or electrochromisms. It is widely reported that o-conjugating polysilanes exhibit these phenomena remarkably clearly.34 However, their structural origins were controversial until recently, since limited information was available on the correlation between the conformational properties of the main chain, electronic state, and (chir)optical characteristics. In 1996, we reported that in various polysilanes in tetrahydrofuran (THF) at 30°C, the main-chain peak intensity per silicon repeat unit, e (Si repeat unit)-1 dm3 cm-1, increases exponentially as the viscosity index, a, increases.41 Although conventional viscometric measurements often requires a wide range of low-dispersity molecular-weight polymer samples, a size exclusion chromatography (SEC) machine equipped with a viscometric detector can afford... 

The insertion of an RC circuit in the feedback electronics right before the high-voltage amplifier for the z piezo has some other advantages. First, much of the high-frequency noise is efficiently filtered out. Second, it facilitates the realization of the electronics for spectroscopic study, which we will discuss in the following section. 

The conformational mobility of a chromophoric main chain polymer is often connected to its electronic structure. Therefore, changes in the UV-visible absorption spectra and/or chiroptical properties are spectroscopically observable as thermo-, solvato-, piezo-, or/and electrochromisms. It is widely reported that a-conjugating polysilanes exhibit these phenomena remarkably clearly [54], However, their structural origins were controversial until recently, since limited information was available on the correlation between the conformational prop-... 

In conclusion, it can be said that the outstanding sensitivity of the spectral absorption and chemical reactivity of our pyridinium-N-phenoxide betaine dyes to small changes in solvent, temperature, pressure, and substituents makes these dyes a very useful class of compounds. They are not only solvatochromic compounds, but exhibit also the phenomena of thermo and piezo-solvatochromism. Their use for setting up different reaction series in order to get Linear Free-Energy Relationships has been demonstrated by the fact that the same betaine dye can be used not only for the introduction of a spectroscopic solvent polarity scale, the so-called E i-scale, but also for the establishment of kinetic and spectroscopic scales of substituents. 

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