https://doi.org/10.1007/PL00021593
NMR approach of the electronic properties of the hydrated trivalent rare earth ions in solution
1
Département de Recherche Fondamentale sur la Matière Condensée,
Service de Chimie Inorganique et Biologique/Reconnaissance Ionique,
CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
2
Laboratoire de Spectrométrie Physique (CNRS-UMR 5588) ,
Université Joseph Fourier, B.P. 87, 38402 Saint-Martin d'Hères Cedex, France
Received:
10
February
1998
Revised:
5
October
1998
Accepted:
16
October
1998
Published online: 15 February 1999
The electronic properties of the lanthanide 
ions are systematically
investigated through the NMR of the protons of the tetramethylammonium ion 
,
used as a probe in 
solution. The effective magnetic moments on the
ions are obtained by measuring the paramagnetic shift of the proton resonance line
due to the demagnetizing field that is proportional to the rare earth concentration.
These results allow to estimate the sizes of the total splitting of the crystal
field acting on the ground multiplet of the various lanthanides.
The measured intermolecular longitudinal relaxation rates of the
protons are compared with the computed values, both of the usual Solomon theory
and of the Curie mechanism. The measured values are intermediate between those predicted
by the two theories. This allows a rather accurate determination of the lifetimes
of the electronic levels of the ions, as they little depend on the details of
the description for the relative spatial microdynamics of the
/ repulsive ion pair.
PACS: 76.60.-k – Nuclear magnetic resonance and relaxation / 76.30.Kg – Rare-earth ions and impurities / 75.10.Dg – Crystal-field theory and spin Hamiltonians
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
