Separation of 47Ti and 49Ti Solid-State NMR
Lineshapes by static QCPMG experiments
EMSL Project ID
7592
Abstract
Due to the structural importance of Titanium in e.g. minerals andglasses a lot of effort has been put into exploring Ti by NMR. Unfortunately, the two NMR active Ti
nuclei, 47Ti and 49Ti, have almost the same Larmor frequency even at the highest possible field today (21.1 T),
are low-gamma nuclei and are generally characterized by a rather large quadrupolar coupling constant that
results in spectra of the central transition that
are more than 100 kHz wide. This results in significant overlap of the lineshapes from the two
isotopes. While this may not be important when
only one Ti site is present it is going to be crucial when the
lineshapes from two or more sites are to be deconvolved. Our interest is in
the observation of distributions of sites in amorphous or partially amorphous
(metamict) materials where broad contributions to spectra from each Ti isotope
make spectral interpretation difficult. If successful these techniques can be
used as a local probe to characterize radiation induced amorphisation in
titanate-based ceramics proposed as hosts for nuclear waste.
Previously we have explored modified versions of the static QCPMG experiment to acquire isotope selective
Ti spectra of the two TiO2 polymorphs anatase and rutile. In the present work we are going to
apply the technique to the titanosilicate glasses NTS2 (Na2O.TiO2.2SiO2) and
KTS2 (K2O.TiO2.2SiO2).
Project Details
Project type
Capability Research
Start Date
2004-05-17
End Date
2006-04-21
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members