A potassium chloride window in an infrared spectrometer is measured

PHYSICS · Subjective · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Lattice dynamics and thermal properties of solids · Lattice dynamics and thermal properties of solids

Condensed Matter Physics, Ch Thermal expansion and lattice thermal conductivity

Problem

A potassium chloride window in an infrared spectrometer is measured, along with the rest of the crystal it was cut from, to have a Gruneisen parameter γG=1.4\gamma_G = 1.4 and a bulk modulus Bmod=18 GPaB_{\rm mod} = 18\,\mathrm{GPa}. Per mole of atoms, as for rock salt in Section 7.3, its heat capacity is CV=25.1 J mol−1K−1C_V = 25.1\,\mathrm{J\,mol^{-1}K^{-1}}, close to 3R3R, and its molar volume is Vm=1.88×10−5 m3 mol−1V_m = 1.88\times10^{-5}\,\mathrm{m^3\,mol^{-1}}. Predict its linear thermal expansion coefficient α\alpha using the Gruneisen relation.

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