Crystal peak effect

Theoretical analyses (75-77) of the matrix-induced changes in the optical spectra of isolated, noble-metal atoms have also been made. The spectra were studied in Ar, Kr, and Xe, and showed a pronounced, reversible-energy shift of the peaks with temperature. The authors discussed the matrix influence in terms of level shift-differences, as well as spin-orbit coupling and crystal-field effects. They concluded that an increase in the matrix temperature enhances the electronic perturbation of the entrapped atom, in contrast to earlier prejudices that the temperature dilation of the surrounding cage moves the properties of the atomic guest towards those of the free atom. 

A general model for electronic relaxation of the Gd3+ S = 7/2 ion in various complexes in solution was presented by Rast el al. [86]. Contrary to the usual assumption, the electronic relaxation in their model is not only due to the effects of the transient zero field splitting, but is also strongly influenced by the static crystal field effect which is modulated by the random Brownian rotation of the complex. Experimental peak-to-peak widths of three gadolinium complexes could be well interpreted as a function of temperature and frequency using three static and one transient crystal field parameters. Moreover, their interpretation of experimental data did not require the addition of any field independent contribution to the line width like the spin-rotation mechanism. 

Figure 10.5 shows the effect of fillers on crystallization peak temperature. The effect of CaCO-, is much less pronounced than that of talc. 

The crystallization peak temperature increased when epoxy resin was added to polypropylene, that is, the uncured and cured epoxy particles acted as effective nucleating agents and accelerated the crystallization of PP in the blends. When cured dynamically, the smaller epoxy particles in the blends resulted in the increase in the number of nucleating agents and hence accelerated the crystallization of polypropylene. Blending polypropylene with epoxy resin resulted in the decrease of crystallinity of polypropylene and increased the melting temperature T of polypropylene than those of pure polypropylene. 

The concentration of Nd can also affect the lineshape and width of the absorption and emission lines in a selective manner, through the crystal field effect related to the ensembles of the Nd " ions. For instance, the linewidth of the " 19/2 " F3/2 absorption of Nd YAG ceramics can be increased by up to 10 %, in the CNd range of 1-9 at.%. This increase in linewidth inevitably leads to reduction in the peak cross sections. In addition, the asymmetric perturbation effects and the variation in the crystal lattice, related to the variation in CNd. also slightly shift the position of... 

The blend of HX4000 (TA/HQ/PHQ) with PEEK is an interesting one because it is one of the few blends where the effect of blending on crystallization of the PLC phase can be examined due to a significant crystallization peak at approximately 275 C which can be observed... 

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