C60 exhibits a glass transition at 90 K, associated with the quenching of the orientational disorder of the fullerene cages. We report evidence from molecular dynamics simulation that a central pair potential model of C60 undergoes a glass transition associated with the quenching of positional disorder from the liquid phase, at Tg ≃ 1100 K for a pressure P = 3.5 MPa, and at higher temperatures for higher pressure values. Two remarkable features turn out to be associated with such a basic prediction: the "effective" packing fraction of the system quantitatively reproduces that of hard spheres at their own glass transition; a strict analogy emerges between our findings and recent mode coupling theory determinations of structural arrest lines in short-range potential models of protein solutions. We argue on such a basis that the conclusions of the present study hold for a wide class of short-range potentials currently in use to model complex fluids, some of biological interest, this suggesting how to achieve at least qualitative predictions of vitrification in these systems.

High-temperature glass transition in model C-60

ABRAMO, Maria Concetta;CACCAMO, Carlo;COSTA, Dino;
2004

Abstract

C60 exhibits a glass transition at 90 K, associated with the quenching of the orientational disorder of the fullerene cages. We report evidence from molecular dynamics simulation that a central pair potential model of C60 undergoes a glass transition associated with the quenching of positional disorder from the liquid phase, at Tg ≃ 1100 K for a pressure P = 3.5 MPa, and at higher temperatures for higher pressure values. Two remarkable features turn out to be associated with such a basic prediction: the "effective" packing fraction of the system quantitatively reproduces that of hard spheres at their own glass transition; a strict analogy emerges between our findings and recent mode coupling theory determinations of structural arrest lines in short-range potential models of protein solutions. We argue on such a basis that the conclusions of the present study hold for a wide class of short-range potentials currently in use to model complex fluids, some of biological interest, this suggesting how to achieve at least qualitative predictions of vitrification in these systems.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11570/1582228
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