Structure, Dynamics, and Phase Transitions in the Fullerene Derivatives C_{60}O and C_{61}H_{2}

Authors

C. Meingast
G. Roth
L. Pintschovius
R. H. Michel
C. Stoermer
M. M. Kappes
Paul A. Heiney, University of Pennsylvania
Laurent Brard, University of PennsylvaniaFollow
Robert M. Strongin, Portland State UniversityFollow
Amos B. Smith III, University of PennsylvaniaFollow

Sponsor

Research at the University of Pennsylvania was supported in part by National Science Foundation Grant No. DMR-MRL-92-20668

Published In

Physical Review B

Document Type

Article

Publication Date

7-1996

Subjects

Epoxy compounds, Hydrocarbons -- Properties, Phase transformations (Statistical physics), Fullerenes -- Neutrons -- Inelastic scattering

Abstract

The effect of perturbing the icosohedral symmetry of C₆₀ by the addition of the side groups -O and -CH₂ upon orientational order-disorder and glass transitions in solid C₆₀ has been studied by a combination of high-resolution capacitance dilatometry and single-crystal x-ray and powder inelastic neutron scattering. Both fullerene derivatives C₆₀O (epoxide) and C₆₁H₂ (6,5-annulene) are shown to undergo a sequence of transitions similar to that found in pure C₆₀, i.e., a first-order orientational ordering transition just below room temperature followed by an orientational glass transition at lower temperatures. Although the exact origin of the glass transition in C₆₁H₂ is unclear, the glass transition in C₆₀O has the same origin as that in C₆₀, with a significantly higher degree of order due to a larger energy difference between pentagon and hexagon orientations. The dilatometric data at the glass transition indicate that, in contrast to C₆₀, the ground-state orientation of both C₆₀O and C₆₁H₂ molecules is that with the smallest volume, also demonstrating a significant influence of the side groups upon the details of the structure. A possible explanation of these differences in terms of steric effects is proposed.

Description

This is the publisher's final PDF. Article appears in Physical Review B (http://prb.aps.org/) and is copyrighted by APS Journals (http://publish.aps.org/). The paper can be found at the following URL: http://dx.doi.org/10.1103/PhysRevB.54.124

Persistent Identifier

http://archives.pdx.edu/ds/psu/11175

Citation Details

Meingast, C. and Roth, G. and Pintschovius, L. and Michel, R. H. and Stoermer, C. and Kappes, M. M. and Heiney, P. A. and Brard, L. and Strongin, R. M. and Smith, A. B. (1996). Structure, dynamics, and phase transitions in the fullerene derivatives C60O and C61H2. 54(1): 124-131.