Thermometers for low temperature Magic Angle Spinning NMR
The measurement of temperature in a Magic Angle Spinning NMR probe in the temperature range 85–300 K is discussed. It is shown that the shift of the 119Sn resonance of Sm 2Sn 2O 7 makes a good thermometer with shift being given by δ = 223 – 9.54 × 10 4/ T ppm and a potential precision of better than...
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Veröffentlicht in: | Journal of magnetic resonance (1997) 2010-05, Vol.204 (1), p.169-172 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The measurement of temperature in a Magic Angle Spinning NMR probe in the temperature range 85–300
K is discussed. It is shown that the shift of the
119Sn resonance of Sm
2Sn
2O
7 makes a good thermometer with shift being given by
δ
=
223 – 9.54
×
10
4/
T
ppm and a potential precision of better than 0.5
K over the entire temperature range. The sensitivity is such (e.g. 4.2
ppm/K at 150
K) that small temperature gradients across the sample can readily be measured. Furthermore, since the spin–lattice relaxation time is very short, measurements can be made in ∼1
s enabling relatively rapid temperature changes to be followed. Values for the chemical shift of
207Pb in Pb(NO
3)
2 down to ∼85
K are also presented. Although the
207Pb shift variation is approximately linear near room temperature (we find a slope 0.725
±
0.002
ppm/K over the range 293–153
K), it clearly deviates from linearity below ∼130
K. |
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ISSN: | 1090-7807 1096-0856 |
DOI: | 10.1016/j.jmr.2010.02.018 |