Temperature Dependence of the Pure Quadrupole Resonance Frequency and Spin—Lattice Relaxation Time in NaBrO3 at Low Temperature

Abstract

The pure quadrupole resonance frequency of Br79 and Br81 in NaBrO3 has been measured between 4.2° and 77.3°K. The spin—lattice relaxation times have been measured between 4.2° and 16°K. The frequency measurements were compared with the Bayer—Kushida theory. While qualitative agreement with the theory is found over the entire temperature interval investigated, the theory does not fit the data in detail. The spin—lattice relaxation times were compared with the theory developed by Chang for NaClO3. If a linear or parabolic temperature dependence of the Br quadrupole frequency is used, as has been the case in all previous work, the theory can be made to agree with the data by appropriately choosing the Debye temperature. However, if the more nearly correct temperature dependence of the quadrupole frequency given by Bayer is inserted into the theory, it is found that no reasonable adjustment of the Debye temperature gives agreement. Fair agreement with the data can be obtained in this case by adjusting the velocities of the longitudinal and transverse lattice waves. Furthermore, at low temperatures the frequency dependence of Bayer leads to nearly equal contributions to the relaxation of Δm=±1 and Δm=±2 transitions, in contrast to the assumption of a linear or parabolic temperature dependence which leads to negligible contribution by the Δm=±2 transitions.

Temperature Dependence of the Nuclear Quadrupole Frequencies of 23Na and 187Re in NaReO4

“…NaC1 0 3 and NaBrC>3 [25][26][27][28][29][30]. For these specimens the temperature dependence of Na is stronger than that one of Cl or Br.…”

Dependence of the pure quadrupole resonance frequency on temperature for KBrO3

“…The temperature of the sample was measured with a germanium resistance thermometer for temperatures below 95 K and with a thermocouple in regions above 95 K. The cryostat used in the experimental arrangement was similar to that described previously. 4 The uncertainty in temperature readings was š0.7% for temperatures <95 K and š0.3% for temperatures >95 K. The failure to obtain data between 95 K (liquid nitrogen temperature) and 293 K (room temperature) was due to the fact that in our experimental set-up a temperature between 95 K and room temperature could not be maintained long enough to measure the resonance frequency. The experimental results are shown in Fig.…”

Dependence of the pure quadrupole resonance frequency on temperature and molar specific heat for NaBrO3

“…The data were obtained with a regenerative spectrometer similar to that described by Koi," with the spectrometer being frequency modulated at a nominal 182. 5 80 Hz. The absorption lines were displayed on a chart recorder, and the resonant frequency at the center of the absorption curve was measured with a Hewlett-Packard 524-C electronic counter.…”