- Conference date: 4-9 June 2006
- Location: Auburn, Alabama (USA)
Carbon nanostructures of various sorts have been the subject of intensive research since their discoveries in the latter part of the 20th century. Much of this research has been motivated by the intrinsic interest of these structures, though their potential as hydrogen storage media has also attracted attention. It was realized that the carbon‐hydrogen interactions in these media would induce dipole moments which might lead to observable absorption of infrared spectra, and this work will be reviewed and extended in this paper. The fundamental vibration‐rotation spectrum, of H2 in a fcc C60 lattice (fullerite) at room temperature was first observed by S. A. FitzGerald and coworkers, who have subsequently extended their observations to near liquid nitrogen temperatures. Herman and Lewis have discussed the theoretical aspects of H2 in carbon nanotube bundles and in fullerite. We have developed a detailed theory for the spectrum of H2 in fullerite. This theory assumes that the H2 ‐ C potential can be accurately approximated by an exp‐6 potential, the parameters of which are then obtained by fitting the line frequencies in FitzGerald’s spectra. We have also obtained a model for the H2 induced dipole moment based on the calculations of Frommhold and coworkers on the induced dipole in H2 ‐ He. With one adjustable parameter this model gives a good account of the observed intensities.
In work to date the line width has been taken as an empirical parameter. However, the line width is in principal determinable from the H2 ‐ C potential and induced dipole moment, together with the known properties of the phonon modes in fullerite. We conclude this paper with a discussion of the line width problem for H2 in fullerite.
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