dc.contributor.author | Bessonette, PWR | en_US |
dc.contributor.author | White, MA | en_US |
dc.date.accessioned | 2013-08-23T15:58:36Z | |
dc.date.available | 2013-08-23T15:58:36Z | |
dc.date.issued | 1999-02 | en_US |
dc.identifier.citation | Reproduced from Bessonette, PWR, and MA White. 1999. "Why is there no low-temperature phase transition in NaOH?." Journal of Chemical Physics 110(8): 3919-3925, with the permission of AIP Publishing. | en_US |
dc.identifier.issn | 0021-9606 | en_US |
dc.identifier.uri | http://dx.doi.org/10.1063/1.478246 | en_US |
dc.identifier.uri | http://hdl.handle.net/10222/36101 | |
dc.description.abstract | Although NaOH and NaOD exhibit parallel polymorphism at high temperatures, NaOD exhibits a
low-temperature phase transition to a hydrogen-bonded antiferroelectric phase and no comparable
transition has been found in NaOH. Measurements of NaOH by dielectric relaxation and adiabatic
calorimetry were undertaken to determine if proton disorder becomes frozen in NaOH at low
temperatures. No evidence for relaxation in NaOH was found from calorimetry or dielectric
measurements. A comparison of the low-temperature heat capacities of NaOH and NaOD showed that NaOH
has excess heat capacity, likely due to the existence of tunneling levels, and this was
satisfactorily fit to a two-level Schottky anomaly. Thus, hydrogen-atom ordering in NaOH appears to
take place through a more gradual process at low temperatures, rather than a low-temperature phase
transition as in NaOD. The difference in the behaviour of NaOH and NaOD likely is associated with
oxygen-oxygen distances that are slightly longer in NaOH than in NaOD, owing to the different nature
of higher-temperature dynamical disorder (classical-double-well potential for OD- and tunneling for
OH-). | en_US |
dc.relation.ispartof | Journal of Chemical Physics | en_US |
dc.title | Why is there no low-temperature phase transition in NaOH? | en_US |
dc.type | article | en_US |
dc.identifier.volume | 110 | en_US |
dc.identifier.issue | 8 | en_US |
dc.identifier.startpage | 3919 | en_US |