Separating the lineshapes of the two NMR active Ti isotopes by static QCPMG solid-state NMR experiments
EMSL Project ID
2542
Abstract
Due to the structural importance of Titanium in e.g. minerals and glasses a lot of effort has been put into exploring Ti by NMR. Unfortunately, the two NMR active Ti nuclei, Ti-47 and Ti-49, 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. In the present work a method that take advantage of the difference in spin (5/2 and 7/2, respectively) for the two nuclei will be used to separate the lineshapes originating 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 distributioins 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 technioques can be used as a local probe to characterise radiation induced amorphisation in titanate-based ceramics proposed as hosts for nuclear waste. The present technique is a modified version of the static QCPMG experiment that e.g. at EMSL has been used extensively to acquire solid-state spectra of Mg, Zn and other low-gamma quadrupolar nuclei. Presently the technique is going to be demonstrated on the two TiO2 polymorphs anatase and rutile.
Project Details
Project type
Capability Research
Start Date
2002-04-01
End Date
2004-04-07
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members