Melting of orientational degrees of freedom
Visualitza/Obre
10.1140/epjst/e2016-60315-4
Inclou dades d'ús des de 2022
Cita com:
hdl:2117/105255
Tipus de documentArticle
Data publicació2017-05
Condicions d'accésAccés obert
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Reconeixement-NoComercial-SenseObraDerivada 3.0 Espanya
Abstract
We use calorimetry and dilatometry under hydrostatic pressure, X-ray powder diffraction and available literature data in a series of composition-related orientationally disordered (plastic) crystals to characterize both the plastic and melting transitions and investigate relationships between associated thermodynamic properties. First, general common trends are identified: (i) The temperature range of stability of the plastic phase Tm-Tt (where Tt and Tm are the plastic and melting transition temperatures, respectively) increases with increasing pressure and (ii) both the rate of this increase, d(Tm-Tt)/dp, and the entropy change across the plastic transition analyzed as function of the ratio Tt/Tm are quite independent of the particular compound. However, the dependence of the entropy change at the melting transition on Tt/Tm at high pressures deviates from the behavior observed at normal pressure for these and other plastic crystals. Second, we find that the usual errors associated with the estimations of second-order contributions in the Clausius-Clapeyron equation are high and thus these terms can be disregarded in practice. Instead, we successfully test the validity of the Clausius-Clapeyron equation at high pressure from direct measurements.
References
CitacióAznar, A., Lloveras, P., Del Barrio, M., Tamarit, J. L. Melting of orientational degrees of freedom. "European physical journal. Special topics", Maig 2017, vol. 226, núm. 5, p. 1017-1029.
ISSN1951-6355
Versió de l'editorhttps://link.springer.com/article/10.1140%2Fepjst%2Fe2016-60315-4
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epjst160315_proof.pdf | 1,012Mb | Visualitza/Obre |