Figure 5. This is a higher magnification of figure 4 showing details of the presumed carbon chain with electron dense materials arranged in a praracrystalline array in the long chain at the right (arrows and the corresponding atoms). We think that the acetylenic carbon chains are "decorated" by the catalyst atoms which promotes nucleation and the final "calf roping act" to integrate these carbon chains into the growing tip. The higher electron density at the ends of the SWNTs is consistent with greater z-numbers of the metal catalyst. The metal atom decoration hypothesis is attractive inasmuch as it could possibly explain the relationship between the growth end and the winding of the linear acetylenic carbon chains into the structure. When the graphitic lattice is made, the heavy metal atoms disengage, and the electron density decreases correspondingly.

14 August 1996

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