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The work is devoted to experimental research of Gruneisen parameter of fullerite C60 (100) single crystal near structural phase transition at 260 K using photoacoustic technique. For measurements automated set-up with laser excitation and piezoelectric registration was used. For illumination of a sample the He-Ne laser was used, which radiation (with wavelength 0.63 microns and power 25 mW) was modulated on intensity on frequency of 32 Hz. The investigated sample of C60 single crystal had the sizes of 5*5*2 mm. Estimation was shown, that thermoelastic regime of photoacoustic signal generation was realized on this frequency, and electronichole system was not influenced on photoacoustic signal. The anomalous behavior of photoacoustic signal was revealed in the fields of temperatures near 260 K. Gruneisen parameter in high-temperature phase is less in two times, than in low-temperature phase, and increases in 5 times in the field of transition at decreasing of temperature.

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