Endothermic freezing on heating and exothermic melting on cooling
Authors: Tombari E., Ferrari C., Salvetti G., Johari G.P.
Autors Affiliation: Istituto per i Processi Chimico-Fisici, Consiglio Nazionale delle Ricerche (CNR), via G. Moruzzi 1, 56124 Pisa, Italy; Department of Materials Science and Engineering, McMaster University, Hamilton, Ont. L8S 4L7, Canada
Abstract: 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. C-p 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 C-p 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.
Journal/Review: JOURNAL OF CHEMICAL PHYSICS
Volume: 123 (5) Pages from: 051104-1 to: 051104-4
KeyWords: CAPACITY; GLASS; DOI: 10.1063/1.2000228Citations: 26data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2023-05-28References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here