Dynamics of CO Molecules in SolidC60as a Function of Cavity Size

Hysteretic phenomena in Xe-doped C60 from x-ray diffraction

“…This circumstance was utilized at the very beginning of the fullerene era resulting in the high-T c superconductivity of an organic crystal (C 60 doped with alkali metals) [1]. Afterwards, C 60 was intercalated with rare gas atoms [2][3][4][5][6][7] and molecules of different symmetries and sizes [8][9][10][11][12][13][14]. It is commonly accepted that changes in the physical properties of fullerite C 60 brought about by intercalation with neutral species are mainly due to the doping-related change in the molar volume.…”

Interaction Between C60 and Gases under Pressure

“…The dynamic behavior of CO has been observed by NMR and IR spectroscopy over large ranges in temperature and pressure (or «prison cell» volume), and the interaction between the guest molecules and the C 60 host lattice has been analyzed in detail. With a decrease in temperature the motion gradually changes from basically free rotation at room temperature to tunneling between a few orientational states at low temperatures [20], and with an increase in pressure a similar restriction in the motion is observed as the available volume decreases [21]. At the highest pressures studied, 3.2 GPa, the molecules must take up oriented positions in the C 60 lattice in much the same way as does CO 2 , and theoretical calculations indicate that the observed spectra agree well with a purely H-oriented C 60 lattice.…”

Intercalation of fullerite C60 with N2 molecules. An investigation by x-ray powder diffraction

“…The FCC lattice parameter of C 60 at 293 K as a function of the occupancy of octahedral sites by inert gas atoms and sample molecules: He (8) [4], Ne (L) [27], Ne (c) [35],Ar (!) [3], (") Ar [4], CO 2 (M) [16], CO (C) [14,15], O 2 (x) [5,11], N 2 (y) [7] and this study, pure C 60 (-) [ [4,34]; (N 2 ) 0.6 C 60 (y) [7,11] [17 -19]; pure C 60 (-) [26,37].…”

“…are orientationally disordered and rotate quite freely in the interstitial sites of the lattice [7,[12][13][14][15]. However, below T c the nonspherical S 6 symmetry of the force field associated with the octahedral sites, with its specific noncentral interaction with the surrounding C 60 molecules, promote localization of the interstitial guest molecule, as well as inducing it to align in certain orientations with respect to the symmetry axes of the C 60 lattice [13][14][15]. This in turn can influence the lattice dynamics, the phase transition and even the structure of the C 60 host matrix.…”