High-resolution thermal expansion of high-pressure polymerized and 'normal' C60 from 10-500 K: Kinetics of depolymerization

• High-resolution capacitance dilatometry was used to study the thermal expansion of both 'normal' and polymer phases of C60. The expansivity, alpha(T), of 'normal' C60 exhibits an unusual temperature dependence above the orientational disordering transition at 260 K; alpha(T) decreases by about 30% from 260 to 500 K and appears to reach a minimum near 500 K. Polymerized C60 has a much smaller expansivity than normal C60 due to the stronger covalent bonding between molecules. The polymerized state converts back to 'normal' C60 at temperatures between 450 and 500 K. We show that this is an activated process with a well-defined activation energy of 1.92 eV and a volume increase of about 2%.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Fullerenes

C60

thermal expansion

dilatometry

polymers

fullerene polymer

Condensed matter physics

Kondenserade materiens fysik

fysik

Physics

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