| dc.contributor.author | White, Mary Anne | en_US |
| dc.contributor.author | Wagner, Brian D. | en_US |
| dc.date.accessioned | 2013-08-23T15:58:37Z | |
| dc.date.available | 2013-08-23T15:58:37Z | |
| dc.date.issued | 1985 | en_US |
| dc.identifier.citation | Reproduced from White, Mary Anne, and Brian D. Wagner. 1985. "The nature of ammonium ion disorder in ammonium tetrafluoroaluminate, NH4AlF4.." Journal of Chemical Physics 83(11): 5844-5848, with the permission of AIP Publishing. | en_US |
| dc.identifier.issn | 0021-9606 | en_US |
| dc.identifier.uri | http://dx.doi.org/10.1063/1.449665 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/36119 | |
| dc.description.abstract | To clarify previous conflicting reports concerning the existence of an order-disorder phase
transition in NH4AlF4 at T ?150 K, the heat capacity of this compd. was measured from T = 15 to 305
K, by adiabatic calorimetry. The calorimetric results show a small anomaly in Cp centered at T = 157
K (?S = 0.02 R), and this is attributed to a soft mode phase transition assocd. with slight changes
in the (AlF4)nn- layers. Anal. of the contribution of NH4 ion disorder to the heat capacity
indicates that the NH4 ion disorder is gradually thermally excited, and can be adequately described
by a 3-dimensional Einstein oscillator for which ?E ?400 K. There is no evidence of an
order-disorder phase transition assocn. with the NH4 ions. | en_US |
| dc.relation.ispartof | Journal of Chemical Physics | en_US |
| dc.title | The nature of ammonium ion disorder in ammonium tetrafluoroaluminate, NH4AlF4. | en_US |
| dc.title.alternative | Section Title: Crystallography and Liquid Crystals | en_US |
| dc.type | article | en_US |
| dc.identifier.volume | 83 | en_US |
| dc.identifier.issue | 11 | en_US |
| dc.identifier.startpage | 5844 | en_US |
