Numéro |
J. Phys. I France
Volume 2, Numéro 11, November 1992
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Page(s) | 2097 - 2105 | |
DOI | https://doi.org/10.1051/jp1:1992270 |
J. Phys. I France 2 (1992) 2097-2105
Absorption spectra of crystalline fullerite 60 at pressures up to 19 GPa
K. P. Meletov, V. K. Dolganov, O. V. Zharikov, I. N. Kremenskaya and Yu. A. OssipyanInstitute of Solid State Physics, Russian Academy of Sciences, 142432, Chernogolovka, Moscow distr., Russia
(Received 2 July 1992, accepted 30 July 1992)
Abstract
The absorption spectra of the thin fullerite crystals,
C60, have been measured in the energy range 1.1-3.1 eV at room temperature and pressures up to 19 GPa. The mean rate of the spectral
pressure shift d
has been estimated for strong- and weak-absorption regions. It has been found that in the strong-absorption region its value
at normal pressure is
-0.15 eV/GPa, and then its absolute value decreases to 0.019 eV/GPa at 12 GPa. The weaker-absorption region located, under normal
pressure, at the red edge shifts much more slowly (
eV/GPa) and coalesces with the strong-absorption region at pressures exceeding 2.0 GPa. The
T=4.2 K measurements indicate the presence of a fine structure in the weak-absorption region of fullerite 60, that transforms to
a step at room temperature. The dependence of the weak-absorption edge shift on the intermolecular distances has been determined
and shown to be governed by the Van der Waals forces of the intermolecular interaction.
© Les Editions de Physique 1992