HAL Id: jpa-00218541
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Submitted on 1 Jan 1979
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AN NGR OBSERVATION OF PROTON JUMPS IN TOURMALINE
H. Pollak, J. Danon, R. Quartier, C. Dauwe
To cite this version:
H. Pollak, J. Danon, R. Quartier, C. Dauwe. AN NGR OBSERVATION OF PROTON JUMPS IN TOURMALINE. Journal de Physique Colloques, 1979, 40 (C2), pp.C2-480-C2-480.
�10.1051/jphyscol:19792166�. �jpa-00218541�
JOURNAL DE PHYSIQUE Colloque C2, supplhent au n O 3, Tome 40, mars 1979, page C2-480
AN NGR 3 B S E R V A T I O N O F PROTON JUMPS I N T O U R M A L I N E
H. Pollak, 3. anon', R. Quartier and C. Dauwe.
UniversitS National du Zazi.e, DSparternent de Physique, Groupe de Z'Etat SoZide, Campus de Kinshasa, ZaiSre
.
+ ~ e n t r o BrasiZeiro de Pesquisas Pisicas, Rio de Janeiro, BrasiZ.
RQsum6.- Une tourmaline ne contenant que des ions ferreux est BtudiBe par spectrometrie ~b'ssbauer entre 4 K et 600 K. Le dedoublement des pics initiaux quand T croyt est attribud 1 des sauts de pro- tons dans le solide.
Abstract.- In Tourmaline the three M-sites share two by two a common edge, thus giving raise to a common oxygen ion (common point CP). Using symmetry considerations hydroxyl groups should be disposed as follows : a group at CP and three groups in the basic plane, such as to respect the trigonal con- figuration.
Tourmaline comonly contains ferrous as well as ferric ions. The special investigated specimen only contains ferrous ones.
With increasing temperature spectra, which at liquid helium display a quadrupole doublet, characte- ristic for a ferrous ion in octahedral symmetry, show shoulders on the inner sides of the doublet. As the temperature still increases, new lines appear with a much smaller quadrupole splitting but with quite the same isomeric shift.
As their quadrupole splittings show a decrease from He 4 K to 600 K toward nearly one half the origi- nal value, they should be attributed to the same ferrous ions in a trans-octahedral site. A proton jumps could be the cause of the observed phenomen. As the CP proton is believed to stay fixed, it is normal that the temperature dependence of the quadrupole splitting is much faster than that of the pure electric field gradient.
It looks like if there could be a proton jumps in solids, very similar to the one observed in chemi- cal solutions. At very low temperature the relaxation mechanism is inhibited as proton rotations in hexamine / 1 /
.
Reference
/ I / Ash, L., Transitions de phase et effet
Miissbauer, rapport CRN 848 ( 1 9 7 4 ) .
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19792166
