Quasielastic neutron scattering study of ammonium ion reorientations in (NH4)2SbF5

✍ Scribed by R. Mukhopadhyay; P.S. Goyal; C.J. Carlile; W.S. Howells

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 317 KB
• Volume: 180-181
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(92)90440-4

✦ Synopsis

Reorientational motion of ammonium ions in (NH,),SbF, is studied using quasielastic neutron scattering. Measurements were made at temperatures between 40 and 300K. The two inequivalent NH: ions present in the unit cell have been identified and associated reorientation times are obtained. The reorientational geometry of the ammonium ions is found to change above and below a transition temperature of 168 K. At 200 K and above, it is probable that the ions rotate about any of the four threefold axes or any of the four twofold axes. At 160 K and below, it is more probable that they rotate about only one of the four threefold axes. Activation energies for the two ions are obtained at different temperature ranges.