Dear colleagues,
I am a little bit puzzled as far as two 19F MAS NMR measurements are
concerned. I thought maybe you have some advice.
The sample is a mica (polylithionite) in which there is only one
fluorine position and the 19F coordinates three cations in octahedral
positions namely 1 Al and 2 Li with two equal distances and one slightly
larger distance. The fluorine occupies the corners of the cation
coordination octahedra. Protons are not in the structure.
In the 12.5 kHz spectrum it looks like the isotropic signal and the
sidebands consist of two signal components. Both first sidebands seem to
have two separate signals in them, especially as the intensities of
these components in the two first sidebands on the left and right are
very different. In the 35 kHz spectrum one clearly sees only one signal.
Both spectra were measured with the same rotor and probehead.
Have you ever encountered something like this, or perhaps have an
explanation why at lower rotational frequencies it looks like two
signals, although that can not be true?
Best regards,
Michael Fechtelkord
--
Dr. Michael Fechtelkord
Institut für Geologie, Mineralogie und Geophysik
Ruhr-Universität Bochum
Universitätsstr. 150
D-44780 Bochum
Phone: +49 (234) 32-24380
Fax: +49 (234) 32-04380
Email: Michael.Fechtelkord_at_ruhr-uni-bochum.de
Web Page: http://www.fechtelkord.de
Received on Mon Aug 27 2018 - 00:19:12 MST