Proton Magnetic Resonance in Liquid Iso-Butyl Bromide
K Luszczynski; J G Powles; K Luszczynski; Physics Department, Queen Mary College, London, E.1; J G Powles; Physics Department, Queen Mary College, London, E.1
Журнал:
Proceedings of the Physical Society
Дата:
1959-10-01
Аннотация:
Proton magnetic resonance relaxation times T<sub>1</sub> and T<sub>2</sub> in liquid iso-butyl bromide [(CH<sub>3</sub>)<sub>2</sub> CHCH<sub>2</sub>Br] have been measured at 21.5 × 10<sup>6</sup> c/s over the temperature range 110°K to 330°K. The results, together with others for T<sub>2</sub> down to 90°K, are interpreted in terms of molecular motion of the molecule as a whole and of the methyl groups in it. This extremely wide temperature range without phase transitions allows a severe test of the validity of theories of nuclear relaxation in molecular substances. The correlation frequency as a function of temperature which ranges from 10<sup>2</sup>c/s to 10<sup>11</sup>c/s is deduced and a remarkably good correlation with dielectric loss measurements is found. A distribution of correlation frequenices of molecular reorientation at low temperatures is confirmed and the effect of the more rapid reorientation of one methyl group is found. This is a case in which the nuclear resonance parameters are controlled principally by the motion of the molecule as a whole but are modified by an internal molecular motion which is considerably faster.
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