First Observation of the FCC to Trigonal/Rhombohedral Transition of Pure Dimerized C60 Under High Pressure.

Autor: Papoular, R. J., Le Parc, R., Dmitriev, V., Davydov, V. A., Rakhmanina, A. V., Agafonov, V.
Předmět:
Zdroj: Fullerenes, Nanotubes & Carbon Nanostructures; Oct-Dec2010, Vol. 18 Issue 4-6, p386-391, 6p, 1 Chart, 5 Graphs
Abstrakt: Similarly to preformed polymeric phases such as 1D-Pmnn [O] or 2D-Immm [T], and in contrast to monomeric FCC C60, dimeric C60 [D or R'] is expected to yield new polymerized phases of higher dimensions when subjected to high pressure. We have carried out an in-situ high-pressure powder diffraction experiment in a diamond anvil cell using MoKα laboratory X-rays, on a pure dimeric sample previously carefully characterized at ambient pressure using synchrotron X-ray HR XRPD and Raman spectroscopy. A transition is indeed observed from 1.2 to 8.6 GPa. A robust analysis shows that the volume per C60 unit decreases from 689 Å3 (0 GPa) to 550 Å3 (8.6 GPa), resulting in a 20% effect. The new phase can no longer be described by a cubic (FCC) unit cell, whereas it can now be indexed and LeBail-refined using a trigonal/rhombohedral unit cell predicted by Dzyabchenko et al. in 1999. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index