Difference between revisions of "Polyamorphic systems"
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| − | Some solid compounds can exist in two or more | + | '''Polyamorphic systems''' and liquid-liquid transitions. Some solid compounds can exist in two or more ''polymorphs'' with different atomic structures but the same chemical composition. |
| − | In the case of a pure element, this behavior is termed | + | In the case of a pure element, this behavior is termed ''allotropy''. |
| − | The existence of liquid polymorphs is known as | + | The existence of liquid polymorphs is known as ''polyamorphism'', i.e. the ability of a substance to exist in several different amorphous modifications. |
Note: glasses are not in thermodynamic equilibrium, so such transformations do not correspond to true phase transitions from one stable liquid to another. | Note: glasses are not in thermodynamic equilibrium, so such transformations do not correspond to true phase transitions from one stable liquid to another. | ||
===Polyamorphic systems=== | ===Polyamorphic systems=== | ||
Revision as of 16:07, 22 February 2008
Polyamorphic systems and liquid-liquid transitions. Some solid compounds can exist in two or more polymorphs with different atomic structures but the same chemical composition. In the case of a pure element, this behavior is termed allotropy. The existence of liquid polymorphs is known as polyamorphism, i.e. the ability of a substance to exist in several different amorphous modifications. Note: glasses are not in thermodynamic equilibrium, so such transformations do not correspond to true phase transitions from one stable liquid to another.
Polyamorphic systems
Real systems that present liquid-liquid transitions:
Models
Idealised models that present liquid-liquid transitions:
- Buldyrev and Stanley model
- Hemmer and Stell model
- Jagla ramp model
- Roberts and Debenedetti model
- Square shoulder + square well
General reading
- C. A. Angell "Formation of Glasses from Liquids and Biopolymers", Science 267 pp. 1924 - 1935 (1995)
- Peter H. Poole, Tor Grande, C. Austen Angell, Paul F. McMillan "Polymorphic Phase Transitions in Liquids and Glasses", Science 275 pp. 322 - 323 (1997)
- Paul McMillan "Phase transitions: Jumping between liquid states", Nature 403 pp. 151-152 (2000)
- Jeff L. Yarger and George H. Wolf "Polymorphism in Liquids", Science 306 pp. 820 - 821 (2004)
