| 1. |
|
|
| 2. |
- Arvanitidis, J., et al.
(författare)
-
High pressure study of the 2D polymeric phase of C60 by means of Raman spectroscopy
- 2001
-
Ingår i: High Pressure Research. - : Informa UK Limited. - 0895-7959 .- 1477-2299. ; 18:1-6, s. 145-151
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of high hydrostatic pressure, up to 12GPa, on the intramolecular phonon frequencies and the material stability of the two-dimensional tetragonal Cm polymer has been studied by means of Raman spectroscopy in the spectral range of the radial intramolecular modes (200-800cm-1). A number of new Raman modes appear in the spectrum for pressures ≈ 1.4 and ≈ 5.0 GPa. The pressure coefficients for the majority of the phonon modes exhibit changes to lower values at P=4.0 GPa, which may be related to a structural modification of the 2D polymer to a more isotropic phase. The peculiarities observed in the Raman spectra are reversible and the material is stable in the pressure region investigated.
|
|
| 3. |
- Arvantidis, J., et al.
(författare)
-
Raman modes of the two-dimensional tetragonal polymeric phase of C60 under high pressure
- 2001
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 114:20, s. 9099-9104
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of high hydrostatic pressure, up to 12 GPa, on the phonon spectrum and the material stability of the two-dimensional (2D) tetragonal C60 polymer have been studied by means of Raman spectroscopy in the frequency range 100-2000 cm-1. A number of Raman modes appear in the spectrum for pressures above ~1.4 GPa, whose intensities increase with pressure. The pressure coefficients of the majority of the phonon modes change gradually to lower values for pressures around 4.0 GPa. The deformation of the C60 molecular cage along with the change of the material to a more isotropic state (as far as its elastic properties are concerned) resulting from the application of high pressure may be causing the observed effects in the Raman spectra. These effects are reversible upon pressure release and therefore the material is stable in the pressure region investigated.
|
|
| 4. |
- Meletov, K. P., et al.
(författare)
-
New pressure-induced phase in tetragonal two-dimensional polymeric C60
- 2001
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 63:5, s. 54106-
-
Tidskriftsartikel (refereegranskat)abstract
- The behavior of the phonon modes of the tetragonal phase of the two-dimensional polymerized C60 has been studied as a function of pressure, up to 27.5 GPa, at room temperature by means of Raman spectroscopy. Gradual transformation of the material to a new phase was observed in the pressure region 19.0–21.0 GPa. As a result of this phase transformation dramatic changes in the Raman spectrum have been recorded. Namely, the total number of bands was reduced and a number of very strong peaks appeared. The Raman spectrum characteristics provide strong indication that the fullerene molecular cage is retained and therefore the high-pressure phase may be related to a three-dimensionally polymerized C60 phase. The high-pressure phase remains stable upon pressure decrease from 27.5 down to 9 GPa. Further release of pressure leads to the destruction of this high-pressure phase to a highly disordered structure whose broad features in the Raman spectrum resemble those of amorphous carbon.
|
|
| 5. |
- Arvanitidis, J., et al.
(författare)
-
Comparative Raman Study of the 1D and 2D Polymeric Phases of C60 under Pressure
- 1999
-
Ingår i: Physica status solidi. B, Basic research. - : John Wiley & Sons. - 0370-1972 .- 1521-3951. ; 215:1, s. 443-448
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of symmetry lowering on the phonon spectra as well as the pressure effects on the vibrational spectrum of polymerized C60 were studied by Raman spectroscopy. Drastic changes related to the splitting of degenerate modes of the C60 molecule were observed together with selected softening of some of them. In spite of many similarities in the Raman spectra of the one (1D) and two-dimensional (2D) polymeric forms of C60, some salient differences in the peak intensities and the appearance of complementary modes are evident. In the Raman spectrum of the 2D polymer under high pressure, new modes, which may be related to the deformations of molecular cages, appear. The observed pressure effects are reversible and the material remains stable for pressures up to 8.8 GPa.
|
|
| 6. |
- Arvanitidis, J., et al.
(författare)
-
High pressure study of the 2D polymeric phase of C60by means of raman spectroscopy
- 2000
-
Ingår i: High Pressure Research. - : Taylor & Francis. - 0895-7959 .- 1477-2299. ; 18:1-6, s. 145-151
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of high hydrostatic pressure, up to 12 GPa, on the intramolecular phonon frequencies and the material stability of the two-dimensional tetragonal C-60 polymer has been studied by means of Raman spectroscopy in the spectral range of the radial intramolecular modes (200-800 cm(-1)). A number of new Raman modes appear in the spectrum for pressures similar to 1.4 and similar to 5.0 GPa. The pressure coefficients for the majority of the phonon modes exhibit changes to lower values at P=4.0 GPa, which may be related to a structural modification of the 2D polymer to a more isotropic phase. The peculiarities observed in the Raman spectra are reversible and the material is stable in the pressure region investigated.
|
|
