Proton Dynamics in KDP Studied by ESR of SeO43-

The hyperfine coupling tensor for the close protons of SeO 4 3- in ferroelectric KDP has been determined, the principal values of which are A 1 =12.1 MHz, A 2 =-21.9 MHz and A 3 =-38.0 MHz. Exchange between two polar Slater configurations has been studied by observing proton and Se 77 hyperfine structures in the paraelectric phase near T C . The exchange frequency obtained from the proton hyperfine structure agrees very well with that from the Se 77 hyperfine structure in the whole range of the experimental temperature. The temperature dependence of the exchange frequency can be approximately represented by the Arrhenius law, where the activation energy and the preexponential factor are 0.19 eV and 4.6×10 13 Hz respectively.