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1.	Wågberg, Thomas, et al. (author) Structural evolution of low-pressure polymerised C60 with polymerisation conditions 1999 In: Journal of Physics and Chemistry of Solids. - : Elsevier B.V.. - 0022-3697 .- 1879-2553. ; 60:12, s. 1989-1994 Journal article (peer-reviewed)abstract We show in this paper that characteristic features in the Raman spectra, especially the frequency of the pentagonal pinch mode, can give information about the polymeric structure of pressure polymerised C60. High-pressure treatment at 1 GPa below 510 K for 3 h results in the formation of a low fraction of dimers only, while treatment at the same pressure and time above 540 K affords a fully polymerised material. In the latter case, different relative fractions of dimers and polymer chains are obtained depending on whether the final reaction conditions were reached by isobaric or isothermal path. We suggest that this difference results from different reaction dynamics in the two cases. The polymerisation rate depends on T and p and on the rotational and orientational states of the molecules. At 1 GPa no polymerisation is observed in sc C60, while in “hexagon” oriented sc C60 at 1.7 GPa dimers are already formed 175 K below the fcc–sc transition and a fully polymerised material is obtained just below the transition to the fcc phase.

Wågberg, Thomas, et al. (author)
Structural evolution of low-pressure polymerised C60 with polymerisation conditions
1999
In: Journal of Physics and Chemistry of Solids. - : Elsevier B.V.. - 0022-3697 .- 1879-2553. ; 60:12, s. 1989-1994
Journal article (peer-reviewed)abstract
- We show in this paper that characteristic features in the Raman spectra, especially the frequency of the pentagonal pinch mode, can give information about the polymeric structure of pressure polymerised C60. High-pressure treatment at 1 GPa below 510 K for 3 h results in the formation of a low fraction of dimers only, while treatment at the same pressure and time above 540 K affords a fully polymerised material. In the latter case, different relative fractions of dimers and polymer chains are obtained depending on whether the final reaction conditions were reached by isobaric or isothermal path. We suggest that this difference results from different reaction dynamics in the two cases. The polymerisation rate depends on T and p and on the rotational and orientational states of the molecules. At 1 GPa no polymerisation is observed in sc C60, while in “hexagon” oriented sc C60 at 1.7 GPa dimers are already formed 175 K below the fcc–sc transition and a fully polymerised material is obtained just below the transition to the fcc phase.

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