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Z. Iqbal Y. Zhang H. Grebel S. Vijayalakshmi A. Lahamer G. Benedek M. Bernasconi J. Cariboni I. Spagnolatti R. Sharma F.J. Owens M.E. Kozlov K.V. Rao M. Muhammed 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(4):509-515
Evidence is presented for the formation of a solid phase based on the smallest fullerene, C20, in thin diamond-like carbon films deposited by ultraviolet laser ablation from diamond onto nickel substrates at room temperature
in the presence of 10-4 torr of cyclohexane or benzene. Laser desorption mass spectrometry from the films shows the presence of C20, C21 and C22 species, while micro-Raman spectroscopy and electron diffraction from selected particles together with first principle density-functional
calculations, indicate a cubic solid with dodecahedral C20 cages as building blocks. Unlike solid C60 and fully protonated C20, which are bound by van der Waals forces, the proposed structure is stabilized by linking of the C20 dodecahedra with bridging carbon atoms at interstitial tetrahedral sites to form a face-centered-cubic lattice with 22 carbon
atoms per unit cell.
Received 10 October 2002 / Received in final form 24 December 2002 Published online 6 March 2003
RID="a"
ID="a"e-mail: zafar.iqbal@njit.edu 相似文献
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Vibrational properties of C20-based solids 总被引:6,自引:0,他引:6
Spagnolatti I. Mussi A. Bernasconi M. Benedek G. 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,38(2):143-145
The European Physical Journal B - The phonon dispersion relations and IR spectrum of a C20-based solid recently identified experimentally [Iqbal et&;nbsp;al. , Eur. Phys. J. B 31, 509 (2003)]... 相似文献
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I.?Spagnolatti M.?BernasconiEmail author G.?Benedek 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):63-67
We investigate an extended spin ladder with diagonal frustrated exchanges in a wide parameter regime. By representing the
model as a sum of semidefinite positive projection operators, we prove that this model has exactly a dimer ground state. Smoothly
changing parameters may lead the model cover several exactly known models. Starting from this ladder model, we proposed two
two-dimensional net models with exact ground states. The quantum phase transition of the ground state, due to the change of
exchange strengths along perpendicular rungs, is also discussed.
Received 13 October 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: schen@thphy.uni.duesseldorf.de 相似文献
4.
I. Spagnolatti M. Bernasconi G. Benedek 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):181-187
The recent synthesis of random schwarzites has stimulated the present ab initio calculation of the electronic structure and electron-phonon interaction in two different periodic D-type schwarzites, fcc-(C28)2 (made of 24 seven-membered rings per unit cell) and fcc-(C64)2 (made of 12 eight membered and 48 six-membered rings per unit cell). Like in fullerenes, also in schwarzites the electron-phonon
interaction potential is found to increase with the absolute Gauss curvature, though it remains smaller than for doped fullerenes.
Received 19 December 2002 Published online 1st April 2003
RID="a"
ID="a"e-mail: marco.bernasconi@unimib.it 相似文献
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I.?Spagnolatti A.?Mussi M.?BernasconiEmail author G.?Benedek 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,37(2):143-148
The phonon dispersion relations and IR spectrum of a C20-based solid recently identified experimentally [Iqbal et al. , Eur. Phys. J. B 31, 509 (2003)] have been computed by density functional perturbation theory. Other competitive structures made by assembling C20 clusters have been considered as well. In particular, we have computed the structure and the Raman spectra of two-dimensional polymeric phases of hydrogenated C20 clusters which might be formed under different synthesis conditions. Fingerprints of the different phases have been identified in the vibrational spectra which could be used in the experimental search of C20-based solids.Received: 29 September 2003, Published online: 15 March 2004PACS:
61.48. + c Fullerenes and fullerene-related materials - 63.20.-e Phonons in crystal lattices - 78.30.-j Infrared and Raman spectra 相似文献
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I.?Spagnolatti M.?BernasconiEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,36(1):87-90
We present the ab initio phonon dispersion relations of
-Ga. The calculations are carried out within density functional perturbation theory by using either norm-conserving pseudopotential and 4s and 4p electrons in the valence or ultrasoft pseudopotential and 3d electrons in the valence as well. The inclusion of 3d electrons in the valence turned out to be necessary to better reproduce the experimental frequencies of the stretching modes of the Ga2 dimers present in the
-Ga structure.Received: 29 July 2003, Published online: 19 November 2003PACS:
63.20.Dj Phonon states and bands, normal modes, and phonon dispersion - 71.15.Nc Total energy and cohesive energy calculations - 71.15.Mb Density functional theory, local density approximation, gradient and other corrections 相似文献
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