Raman phonon

FIGURE 1 Raman phonon modes in AlxGai.xN versus alloy composition. Symbols represent symmetry of the modes, symbol fillings the original papers, (a) is an enlargement of the low composition range in (b). 

Fig. 8. Temperature dependence of the Raman phonon modes of C60 (from van Loosdrecht et al. [24]).

Fig. 19. Raman phonon frequencies of C60-TDAE titrated against x for Cg0 (from Muthu et al. [48]).

Figure 6.8-18 The Raman phonon spectra of 2-benzyl-5-benziliden-cyclopentanone at room temperature (top) and at 77K.

Prasad et al. (1982) have described Raman investigations of solid state reactions. They show that it is advantageous to obtain the spectra at lower temperature, typically at 120 K. Lower frequency phonon spectra show considerable broadening at room temperature, so that details of spectral features are lost. Raman phonon spectra of 2-benzyl-5-benzilidene cyclopentanone at room temperature and at 77 K (see Fig. 6.8-18) indicate that lower temperature improve.s the resolution of the spectral features. This phenomenon can be used for a detailed analysis in order to elucidate the reactivity of a compound at room temperature. However, it is necessary to make sure that neither the reactant nor the product undergoes a structural phase transition between room temperature and the low temperature at which the spectrum is recorded. This is confirmed by studying the phonon spectra as a function of the temperature. 

Figure 6.8-20 Raman phonon spectra of a-DSP at 95 K obtained as a function of the grade of polymerization.

Chandrasekhar M, Renucci JB, Cardona M (1978) Effects of interband excitations on Raman phonons in heavily doped n-Si. Phys Rev B 17 1623-1633... 

Hence, we find that the phonon spectrum Is a sensitive probe for the molecular mechanism of reaction In the condensed phase. The Raman phonon spectra, monitored during the conversion of the oligomer to the polymer, show that initially the process starts homogeneously, with considerable lattice rearrangement. Then It turns heterogeneous, with a phase separation accompanied by a gradual ordering of the polymer product lattice. 

Figure 1. Raman phonon spectra of a-DSP monomer (top), oligomer (middle), and polymer (bottom) at room temperature. The spectral resolution is ca.icm. ...

Figure 4 shows a plot of the Raman phonon frequency as a function of distance from the edge of the oxide island. The figure also shows the dependence of the stress (as extrapolated from the Raman frequency) on the position of the probe. 

Interestingly, the reaction is specific for the methyl ester the allyl, 1-butyl and 2-butyl esters do not undergo similar rearrangement. This may well be a result of different molecular orientations in these crystals. From a Raman phonon spectroscopic study of the rearrangement, it has been deduced that reaction 10 proceeds by a heterogeneous transfer mechanism that is, the reaction is initiated at random throughout the crystal and terminates where there are random molecular dislocations49. 

The apex Raman phonon and 8. Overdoped phase - III phase separation in ... 

Estimation of the Raman phonon intensities is even more complex, though a model has been proposed for this quantity that is suitable for potential based methods (Kleinman and Spitzer 1962). The electric susceptibility tensor is given by ... 

If solids are irradiated with ultrasound having a frequency below the nuclear Larmor frequency, reference to the discussion of the Raman phonon relaxation process indicates that relaxation emission... 

G. Ouyang, C.Q. Sun, W.G. Zhu, Pressure-stiffened Raman phonons in group III nitrides A local bond average approach. J. Phys. Chem. B 112(16), 5027-5031 (2008)... 

M.S. Liu, L.A. Bursill, S. Prawer, R. Beserman, Temperature dependence of the first-order Raman phonon lime of diamond. Phys. Rev. B 61(5), 3391-3395 (2000)... 

Carron LM, Andres A, Lopez MJM, Casais MT, Alonso JA. Raman phonons as a probe of disorder, fluctuations, and local structure in doped and undoped orthorhombic and rhombohedral manganites. Physical Review B 2002 66 174303. 

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