New measurements of the Raman spectrum of potassium selenate

Abstract

Abstract The Raman spectrum of K2SeO4 has been re-measured at 140 K and 110 K with neon line calibration and numerical fitting of peak frequencies to obtain ±0.1 cm−1 precision. Although the results at 140 K confirm the measurements of the internal mode peak frequencies reported by Unruh which appear to agree with the factor group predictions for the perfect crystal, arguments are presented to show that the orientationally-disordered selenate model still holds. Additional measurements in the incommensurate phase at 110 K revealed line-splitting similar to those reported for infrared spectra; a comparison with those results is given.