The first-order Raman frequency shifts of the A g(2) + B g(2) mode in a CaWO 4 crystal were measured in the temperature range of 77 ∼ 771 K. The frequency shift for this mode changes very slowly with increasing temperature. The temperature dependence of the frequency shift of the A g(2) + B g(2) mode was analyzed using the lattice dynamical perturbative treatment. We found that the quartic anharmonic term of the first-order perturbation, as well as the cubic term of the second-order one, and thermal expansion contribute to the temperature dependence of the frequency shift of the A g(2) + B g(2) mode in a CaWO 4 crystal.KEYWORDS: Raman frequency shift, cubic and quartic anharmonic term, thermal expansion, lattice dynamical perturbative treatment * Present address:

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