%0 Journal Article
%T Interplay between H-bonding proton dynamics and Fe valence fluctuations in Fe 3 ( P O 4 ) 2 ( OH ) 2 at high pressure
%+ Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM)
%+ Laboratoire Charles Coulomb (L2C)
%+ Synchrotron SOLEIL (SSOLEIL)
%A Hearne, G.
%A Ranieri, V.
%A Hermet, P.
%A Haines, J.
%A Cambon, O.
%A Bantignies, J.
%A Fertey, P.
%A Stuerzer, T.
%A Poienar, M.
%A Rouquette, J.
%< avec comité de lecture
%@ 2469-9950
%J Physical Review B
%I American Physical Society
%V 107
%N 6
%P L060302
%8 2023-02-07
%D 2023
%R 10.1103/PhysRevB.107.L060302
%Z Physics [physics]Journal articles
%X We pressure tune the hydrogen bond in Fe-O-H⋅⋅⋅O-P structural segments of mixed-valence barbosalite (Fe 2+ Fe 3+ 2)(PO4)2(OH)2. Infrared spectroscopy evidences changes in softening of O-H stretch modes and excessive profile broadening onset below 10 GPa. Single-crystal X-ray diffraction shows pseudo-symmetrization of the original monoclinic unit cell concurs with these changes in the O-H vibrational mode. These are considered compelling indicators of proton delocalization onset below 10 GPa as hydrogen bonds are strengthened under pressure. Subsequently in the range 10−30 GPa, Fe Mössbauer spectroscopy discerns Fe 2+ ⇔ Fe 3+ valence fluctuations at proximate cations of the hydrogen bonds. When the original crystal potential at an Fe 2+ site is perturbed by proton delocalization at a ligand, electron exchange is induced along Fe 2+ →L→Fe 3+ pathways (ligand L = O or (OH)-of shared octahedral faces). Thus, (Fe 2+ Fe 3+ 2)(PO4)2(OH)2 under pressure exemplifies the interplay between proton (THz) and electron (MHz) dynamics on two disparate time scales in the same condensed phase.
%G English
%2 https://cnrs.hal.science/hal-04037182/document
%2 https://cnrs.hal.science/hal-04037182/file/Barbosalite-Pressure-V25-PRBLETT-RESUBMIT.pdf
%L hal-04037182
%U https://cnrs.hal.science/hal-04037182
%~ CNRS
%~ ENSC-MONTPELLIER
%~ ICG
%~ L2C
%~ INC-CNRS
%~ SYNCHROTRON-SOLEIL
%~ CHIMIE
%~ UNIV-MONTPELLIER
%~ GS-PHYSIQUE
%~ INSTITUT-SCIENCES-LUMIERE
%~ UM-2015-2021
%~ UM-EPE
%~ TEST2-HALCNRS