التفاصيل البيبلوغرافية
| العنوان: |
Endothermic freezing on heating and exothermic melting on cooling. |
| المؤلفون: |
Tombari, E.1, Ferrari, C.1, Salvetti, G.1, Johari, G. P.2 johari@mcmaster.ca |
| المصدر: |
Journal of Chemical Physics. 8/1/2005, Vol. 123 Issue 5, p051104. 4p. 3 Graphs. |
| مصطلحات موضوعية: |
*CRYOBIOLOGY, *COOLING, *CRYSTALLIZATION, *PROPERTIES of matter, *THERMODYNAMICS, *VISCOSITY |
| مستخلص: |
Generally, a liquid freezes exothermally on cooling and a crystal melts endothermally on heating. Here we report an opposite occurrence—a liquid’s endothermic freezing on heating and the resulting crystal’s exothermic melting on cooling at ambient pressures. Cp decreases on freezing and increases on melting, and the equilibrium temperature meets the thermodynamic requirement. Melting on cooling takes longer than freezing on heating. A rapidly cooled crystal state becomes kinetically frozen, evocative of a nonergodic state. Both Cp and enthalpy relax like those of glasses, though the viscosity is only a few centipoise. The crystal state belongs to energy minima higher than those of the melt, which has consequences for the use of potential-energy landscape, or inherent structures, for a thermodynamic description of a material. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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