2024-03-29T15:54:24Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/568122022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116X-ray study of the modulation-wave structure in thioureaTakahashi, IsaoOnodera, AkiraShiozaki, Yoichiopen access© 1987 The American Physical Society420A longitudinal component of the modulated structure of thiourea SC(NH2)2 which corresponds to the translational mode transformed under the irreducible representation B3g in D2h has been observed by x-ray diffraction. The parameters including the longitudinal component are examined. The longitudinal component accounts well for the asymmetry of pairs of the satellite intensities (hkl±δ). The phase of the longitudinal wave differs by π/2 from those of the transverse waves of B2u symmetry, which corresponds to the ferroelectric soft mode. The amplitude of the longitudinal wave is as small as 10-1 times those of the transverse waves. A possible interpretation on the longitudinal mode is given by considering the short-range interaction between molecules: It suggests that the longitudinal component, as well as the transverse components, plays an important role in the occurrence of the incommensurate phase of thiourea.American Physical Society1987-11-01engjournal articleVoRhttp://hdl.handle.net/2115/56812https://doi.org/10.1103/PhysRevB.36.70080163-1829AA00362255Physical Review B361370087012https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/56812/1/PhysRevB.36.7008.pdfapplication/pdf188.43 KB1987-11-01