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
Hauptverfasser: Kemp, T.F., Balakrishnan, G., Pike, K.J., Smith, M.E., Dupree, R.
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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.
ISSN:1090-7807
1096-0856
DOI:10.1016/j.jmr.2010.02.018