Binary fluid mixtures: effects of varying the mean valency
Titel:
Binary fluid mixtures: effects of varying the mean valency
Auteur:
SPEEDY, ROBIN J.
Verschenen in:
Molecular physics
Paginering:
Jaargang 89 (1996) nr. 4 pagina's 1121-1131
Jaar:
1996-11-01
Inhoud:
Constraint theory predicts, from topological considerations alone, that covalently bonded glasses change from floppy to rigid when the mean valency <r> increases through a threshold value <r> = 2·4. There is evidence for extrema in several properties of liquid mixtures of Ge, As, and Se when the mean valency is 2·4. To test the possibility that liquid mixtures in general may show anomalies when <r> = 2·4 the pressure, bond lifetime, network persistence time and the self-diffusion coefficient were measured in mixtures of two- and three-valent saturated square-well molecules in which the mean valency <r> is varied from 2 to 3 in steps of 1/8, the inverse temperature e/kT is varied from 0 to 4, and the density is varied from a gas-like value to near the glass transition. The measured properties are insensitive to <r>, they vary monotonically with <r> and there are no indications of special effects near <r> = 2·4.
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