抄録
The nuclear quadrupole resonance frequencies of I127 in stannic tetraiodide (SnI4), As75 in arsenolite (As4O6), Br81 in paradibromobenze (p-C6H4Br2) and in potassium bromate (KBrO3) were measured as a function of hydrostatic pressure at various temperatures. The pressure range was 1–9000 kg/cm2 in the temperature range from −77° to 100°C, and 1–1000 kg/cm2 at liquid oxygen temperature, respectively.
In general, the pressure and the temperature dependence of the resonance frequency is found to agree with Bayer’s theory incorporated with Kushida-Benedek-Bloembergen’s theory. It is noticed, however, that an anisotropic change of the internal parameters for the positions of atoms in a unit cell would contribute appreciably to the analysis of the data even in the cases of cubic crystals, SnI4 and As4O6 and that a deviation from the Bayer curve is observed in As4O6. Doublet lines for SnI4 are found to behave differently as a function of volume, and it is concluded for the molecular crystal, As4O6 that the effective modes of lattice vibration which are responsible for the temperature dependence of the resonance frequency, are intra-molecular modes rather than a tipping mode of the molecule as a whole.
