Proton motions in hydrogen-bonded ferroelectric and antiferroelectric solids. Part 1.—Energy-loss neutron incoherent-scattering spectra of KH2PO4 and Ag2H3IO6 for T < Tc
Abstract
The energy-loss neutron incoherent-scattering spectra for the ferroelectric and antiferroelectric phases of KH2PO4 and Ag2H3IO6 respectively are reported in the interval 280–1400 cm–1. The transverse proton modes have been identified in both ferroelectric solids; the i.-r. spectrum of paraelectric Ag2H3IO6 in the frequency interval 50–1500 cm–1 has been assigned on the basis of symmetry correlation. An additional mode, which must involve some protonic motion, has been observed at 570 cm–1 in the low-temperature phase of KH2PO4; the PO–4 molecular vibrations of KH2PO4 are compared with the neutron spectra of K2HPO4 in the interval 280–1200 cm–1.