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D. Le Pévelen J. Gaultier Y. Barrans D. Chasseau F. Castet L. Ducasse 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(3):363-373
The crystal structure of (TMTSF)2ClO4 has been determined at (7 K, 1 bar) and at (7 K, 5 kbar) with a high accuracy. For the latter, low temperature and pressure
were applied simultaneously using a X-ray diffraction instrumentation designed in our laboratory, these results are the first
for molecular compounds. The effects of lowering the temperature are not the same as those produced by increasing the pressure.
At (7 K, 1 bar) the anion ordering which occurs in this compound, and which is characterised by the appearance of b
*
/2 superlattice reflections, is well observed. This anion ordering leads to the presence of two independent stacks of TMTSF
cations which is the only case found in the Bechgaard salts family. The comparison of the low temperature crystal structures
under atmospheric pressure and at 5 kbar shows that the centres of mass are nearly the same, independent of the pressure:
the interchain interactions do not depend on the doubling of the unit cell. Under pressure, the ordering (0, 1/2, 0) does
not occur at any temperature. These structural data are confirmed by the quantum chemical calculations which show that the
difference in the site energy of the two independent cations is 100 meV.
Received 10 April 2000 and Received in final form 27 September 2000 相似文献
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G. Felix R. Lapouyade A. Castellan B. Bouas-Laurent J. Gaultier C. Hauw 《Tetrahedron letters》1975,16(6):409-412
In contrast to previous reports, the colourless products obtained in the preparation of 1,2 bis (9′-anthranyl) ethanes are not the photoisomers but new polycyclic compounds of type which we propose to call lepidopterenes, on account of their suggestive shape. 相似文献
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