1A-3
Proton transfer assisted by far-infrared phonons in K3H(SO4)2, Y. Hashimoto (Tohoku Univ.) et al.
Anomalous temperature changes in K3H(SO_4)2 are observed above 400 K in the broad SO4 tetrahedral deformations accompanied by SO stretching at around 700 and 850 cm-1 (ν700, ν850), whose vibrational motifs are characterized by the displacement of protons parallel to the c direction and the ab plane, respectively. The anomaly reflects the enhancement of protonic fluctuations, indicating that ν700 and ν850 are the phonons that assist proton hopping between dimers. This result suggests the emergence of proton polarons synchronized with those phonons.