Polyaromatic experimental results

Table 2 The isotropic magnetizability (in ppm cgs) of some polyaromatic hydrocarbons as obtained with Pauling s model [36] and using ab-initio methods. The experimental results given by Pauling are also listed. The numbers in parentheses are obtained by scaling the experimental results by a factor of 1.1 (see Section 8). All calculations were made with idealized C — C bond distances of 1.42A and C — H bond distances of 1.07A.

Kosower and co-workers have found the photoinduced, barrierless charge separation processes of substituted polyaromatics to be controlled by solvent relaxation behavior over a large temperature range in alcohol solvents. Heitele and Michel-Beyerle reported on the complex solvent- and temperature-dependent electron transfer fluorescence quenching in some covalently linked aromatic donor-acceptor compounds in viscous solvents. These authors have attempted a critical comparison between current theoretical models and their experimental results, and the limitations of current theoretical models are discussed. 

At the same time calculations on the modified MEIS are possible without additional kinetic models and do not require extra experimental data for calculations, which makes it possible to use less initial information and obviously reduces the time and labor spent for computing experiment. Furthermore, there arise principally new possibilities for the analysis of methods to mitigate emissions from pulverized-coal boilers, since at separate modeling of different mechanisms of NO formation the measures taken can result in different consequences for each in terms of efficiency. Consideration of kinetic constraints in MEIS will substantially expand the sphere of their application to study other methods of coal combustion (fluidized bed, fixed bed, etc.) and to model processes of forming other pollutants such as polyaromatic hydrocarbons, CO, soot, etc. 

Compared with APCI, APPI is more sensitive to the experimental conditions. Properties of solvents, additives, dopants or buffer components can strongly influence the selectivity or sensitivity of the detection of analytes. Nevertheless, this technique allows the ionization of compounds not detectable in APCI or ESI, mainly non-polar compounds. For these last compounds, APPI is a valuable alternative. Thus, APPI is a complementary technique to APCI and ESI. However, for a given substance it remains difficult to predict which ionization source (APPI, APCI or ESI) will give the best results. Only preliminary tests will allow the choice of the best ionization source. APPI appears to be efficient for some compound classes such as flavonoids, steroids, drugs and their metabolites, pesticides, polyaromatic hydrocarbons, etc. [85],... 

Recently, Montes-Moran and co-workers have discussed the virtues and drawbacks of the different hypotheses about basic carbon sites in view of experimental and theoretical results [68]. They conclude that the basicity of the n electron density of the basal planes is weak and suggest that the overall basicity of the carbon surface is mainly due to the contribution of oxygen functional groups, and the existence of pyrone-type structures on the edges of the polyaromatic layers. 

A reassessment of the experimental data concerning the catalytic hydrogenation of polyaromatic hydrocarbons by cobalt carbonyl under oxo conditions has resulted in the postulate that the reaction involves free radicals rather than organocobalt complexes. ... 

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