Dynamics of protonic conductorsRb3H(SO4

EPR Study of VO2+Center in Fast Proton Conductor K3H(SO4)2

“…The averaging of direction cosines is in agreement with Rb 87 NMR data in isomorphous Rb 3 H(SO 4 ) 2 crystal [15], where only one Rb + ion position about 50 K below T sp was observed, whereas three positions at RT. This is a result of the averaging of electric field gradient (EFG) tensor experienced by Rb + /K + ions.…”

Hydrogen transport in superionic system Rb3H(SeO4)2: A revised cooperative migration mechanism

“…In the theoretical works 16,[18][19][20][21][22] , the two-stage Grotthuss mechanism is frequently considered within phenomenological free-particle approches which typically contain two stages: (1) translation of proton within a hydrogen bond between the nearest ionic groups XO 4 ; (2) inter-bond proton transfer related to reorientations of the ionic groups XO 4 . Howerer, the experimental studies demonstrate that the transport of protons is a highly complex process which can be characterized as a transfer of hydrogen ion in the course of the reactions of creation and breaking of HXO 4 bonds.…”

Proton spin-lattice relaxation and local symmetry of the H bond inRb3H(SO4Mikac1, Zalar2, Dolinšek3 et al. 2000Phys. Rev. BSelf Cite12170View full textAdd to dashboardCite

“…We also wished to compare the local symmetry of the O-H¯O bond in Rb 3 H͑SO 4 ͒ 2 with the symmetry of the O-D¯O bond in Rb 3 D͑SO 4 ͒ 2 above and below the antiferroelectric transition at T c ϭ82 K. 2,3,4,5 II. STRUCTURAL BACKGROUND Rb 3 H͑SO 4 ͒ 2 and related A 3 H(XO 4 ) 2 compounds (A ϭK, Rb, Cs; XϭSe, S) consist of isolated ͓(XO 4 ) -H¯(XO 4 )͔ 3Ϫ dimers separated by A ϩ ions and are thus often described as ''zero-dimensional'' H-bonded systems.…”

“…The proton T 1 Ϫ1 at 37 and 18 MHz strongly decreases with decreasing temperature between 300 and 10 K and becomes temperature independent below 10 K. The activation energy for this motion is significantly lower than the activation energy 0.82 eV found for the deuteron inter-H-bond motion 2 -connected with DSO 4 reorientation-in Rb 3 D͑SO 4 ͒ 2 . Two-dimensional ͑2D͒ deuteron NMR exchange measurements 2 have further shown that the correlation frequency for the deuteron inter-H-bond motion is as low as 2.16 Hz at 290 K. It would become astronomically slow below 100 K. This means that HSO 4 rotation and proton inter-H-bond motion cannot be responsible for the observed strong temperature dependence of the proton T 1 in Rb 3 H͑SO 4 ͒ 2 below 300 K and that this temperature dependence very probably arises from proton intra-H-bond motion.…”