Europhys. Lett.
Volume 48, Number 6, December 1999
Page(s) 662 - 666
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00535-4

Europhys. Lett, 48 (6), pp. 662-666 (1999)

The non-exponential relaxation of the C60 crystal around glass transition temperature

F. Yan 1, Y. N. Wang 1 and J. S. Liu 2

1 National Laboratory of Solid State Microstructures, Institute for Solid State Physics
Center for Advanced Studies in Science and Technology of Microstructures
Department of Physics, Nanjing University - Nanjing 210093, PRC
2 Center of Advanced Studies, Tsinghua University - Beijing 100084, PRC

(received 28 April 1999; accepted in final form 11 October 1999)

PACS. 64.70Pf - Glass transitions.
PACS. 61.48${\rm +c}$ - Fullerenes and fullerene-related materials.
PACS. 02.50Ng - Distribution theory and Monte Carlo studies.


A model of the energy barrier of a molecule between two orientational states in the $\rm C_{60}$ crystal, which depends on the neighboring molecules, is first proposed. Based on this model, the orientational relaxation of $\rm C_{60}$ molecules around 90 K was simulated with the Monte Carlo method. The simulation results show that the relaxation is slightly non-exponential and can fit the Kohlrausch-Williams-Watts (KWW) function with the non-exponential factor $\beta=0.962\pm 0.002$, which is equal to the experimental data that has not been explained before.


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