Poly optical spectroscopy

Since for the diarylpolysilanes, as for all polysilanes, the main chain is chromophoric due to the electronic transition between the delocalized silicon a and a orbitals, the electronic spectroscopies of CD, UV-Vis, and FL are particularly powerful probes of the structures of these materials. The magnitude of dimensionless quantity, gabs, is perhaps the most useful in comparing the CD spectra of optically active poly(diarylsilane)s. 

AR Brown, K Pichler, NC Greenham, DDC Bradley, RH Friend, and AB Holmes, Optical spectroscopy of triplet excitons and charged excitations in poly(p-phenylenevinylene) light-emitting diodes, Chem. Phys. Lett., 210 61-66, 1993. 

In relation to these works, the reaction of p-nitrophenyl esters with optically active poly( propyleneimine )(8) was studied at 25°C in DMSO solution according to the same procedure described for the case of poly-L-lysine derivatives. The poly( propyleneimine ) derivatives thus obtained have different IR and UV absorption spectra from those of the starting compounds, and show absorptions assigned to the nucleic acid bases. However, their contents determined by UV spectroscopy were substantially low as compared with the case of poly-L-lysine derivatives for (9) and (20), the base contents were below 30 and 50 %, respectively. The result was explained by a steric hindrance caused by methyl groups on the main chain of poly( propyleneimine ) ... 

Brown PJ, 8irringhaus H, Harrison M, 8hkunov M, Friend RH (2001) Optical spectroscopy of field-induced charge in self-organized high mobility poly(3-hexylthiophene). Phys Rev B 63 125204... 

Crosslinking of EPDM and Poly diene Rubbers Studied by Optical Spectroscopy... 

Ultrasonic interferometry, in which the travel time of high-frequency elastic waves through a sample is measured, also yields elastic moduli. Because it is a physical property measurement, rather than an optical spectroscopy, it can be used equally well on poly-crystalline samples as single-crystals, although polycrystalline measurements only yield the bulk elastic properties, bulk modulus and shear modulus, G. High-pressure ultrasonic interferometry techniques were initially developed in the piston cylinder... 

Optical Spectroscopy. Figure 7 shows the optical spectra of solution cast (from slowly evaporated methylene chloride solution) poly(, 8-nonadlyne) films which have been exposed to UV light (1600 uW/cm at 254 nm, under UHP argon purge) for various times. The macromonomer has no absorbance maxima In the region shown, whereas, samples with less than about 5 minutes exposure have two dlscernable maxima- at 575 nm and 630 nm. At low conversions (about 2 to 11... 

National Science Foundation Optical density Postapply bake Photoactive compound Photochemical acid generator Positron annihilation spectroscopy Poly(fert-butoxycarbonyloxystyrene)... 

Yamamoto, T. et al., Extensive studies on Jt-stacking of poly(3-alkylthiophene-2,5-diyl)s and poly (4-alky lthiazole-2,5-diyl)s by optical spectroscopy, NMR analysis, light scattering analysis, and x-ray crystallography, J. Am. Chem. Soc. 120, 2047-2058, 1998. 

Spano, RC. 2005. Modeling disorder in polymer aggre tes The optical spectroscopy of regiore-gular poly(3-hexylthiophene) thin films. J Chem Phys 122 234701. 

K. E. Ziemelis, A. T. Hussain, D. D. C. Bradley, R. H. Friend, J. Ruehe, G. Wegner, Optical spectroscopy of field-induced charge in poly(3-hexylthienylene) metal-insulator-semiconductor structures evidence for polarons, Physical Review Letters 1991, 66, 2231. 

Although poly(para-phenylene vinylene), or PPV, was the first phenyl-based polymer to exhibit electroluminescence its slightly more complicated chemical structure than PPP means that PPP is a more convenient model system to study theoretically. Nonetheless, the remarkable similarities in the optical spectroscopy of the two systems means that we should seek a common description of their excited states. Indeed, as we explain in this section, the theoretical description of the excited states of PPV, apart from overall energy differences, is very similar to PPP. 

Pichler, K., Halliday, D., Bradley, D.C., Burn, P.L., Friend, R.H., and Holmes, A.B. (1993) Optical spectroscopy of highly ordered poly(p-phenylene vinylene). f Phys. Cond. Matter, 5, 7155. 

The cadmium chalcogenide semiconductors (qv) have found numerous appHcations ranging from rectifiers to photoconductive detectors in smoke alarms. Many Cd compounds, eg, sulfide, tungstate, selenide, teUuride, and oxide, are used as phosphors in luminescent screens and scintiUation counters. Glass colored with cadmium sulfoselenides is used as a color filter in spectroscopy and has recently attracted attention as a third-order, nonlinear optical switching material (see Nonlinear optical materials). DiaLkylcadmium compounds are polymerization catalysts for production of poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVA), and poly(methyl methacrylate) (PMMA). Mixed with TiCl, they catalyze the polymerization of ethylene and propylene. 

In this study, we extend the range of inorganic materials produced from polymeric precursors to include copper composites. Soluble complexes between poly(2-vinylpyridine) (P2VPy) and cupric chloride were prepared in a mixed solvent of 95% methanol 5% water. Pyrolysis of the isolated complexes results in the formation of carbonaceous composites of copper. The decomposition mechanism of the complexes was studied by optical, infrared, x-ray photoelectron and pyrolysis mass spectroscopy as well as thermogravimetric analysis and magnetic susceptibility measurements. 

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