Infrared dispersion of β-gadolinium molybdate at room temperature

Infrared reflection spectra parallel and perpendicular to the ferroelectric c-axis of the (A1) and (B1, B2) modes at room temperature are reported as obtained with a Fourier-transform scanning interferometer. The spectra are analysed with the four parameter factorized form of the dielectric function. The infrared-active mode parameters as well as the effective charges of the constituents as deduced from the splittings of the polar modes are reported. The spontaneous polarization is calculated assuming effective charges of Gd and MoO4 ions to P/sub s/ = -0.19 x 10-2 C/m2 in agreement with experimental data. (author)