Neutron scattering from ammonium salts. I. Coexisting phases in NH<sub>4</sub>I and NH<sub>4</sub><sup>+</sup> dynamics in phase I and II
P S Goyal; B A Dasannacharya; P S Goyal; Nuclear Phys. Div., Bhabha Atomic Res. Centre, Bombay, India; B A Dasannacharya; Nuclear Phys. Div., Bhabha Atomic Res. Centre, Bombay, India
Журнал:
Journal of Physics C: Solid State Physics
Дата:
1979-01-28
Аннотация:
Neutron quasi-elastic and elastic scattering experiments from NH<sub>4</sub>I are reported in the temperature range 213K-300K. It is shown that both while cooling and heating, one obtains an NaCl phase coexisting with low-temperature phases. This calls for great care in interpreting any data on NH<sub>4</sub>I in this temperature range. The reorientation times for NH<sub>4</sub><sup>+</sup> ions in the CsCl phase are determined. In the NaCl phase it is shown that a simple rotational diffusion model does not describe NH<sub>4</sub><sup>+</sup> reorientations properly.
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