8. Optical methods for determining the concentration and particle size

S.V. Ivanova
P.N. Lebedev Physical Institute of RAS

Pequliarities of light scattering by quartz crystal

In the present work has been performed the investigations of nonlinear properties of photorefractive quartz crystal in wide range of temperature (20-800°C). The temperature behavior of Raman spectra have been observed in frequency range of 0-300 cm-1. The intensity of mode 206 cm-1(in maximum) undergoing the knee near 400°C. At the temperature of α-β phase transition (573°C) this line decreases and appears in the β-phase. Intensity of the line 266 cm-1 linearly decreases at increases of temperature. The modes of 147 and 128 cm-1 coincide at 406°C and undergoing the maximum of light scattering at this temperature. It can be made conclusion that at range of 400°C was discovered the new phase transition of second order
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