4 dimensional BEC of gases inside nanotube bundles
Abstract
Helium atoms or hydrogen molecules can be strongly bound inside interstitial channels within bundles of carbon nanotubes. The effects on adsorption of a nonuniform distribution of tubes are evaluated. The energy of a single particle state is the sum of a discrete transverse energy Et (that depends on the radii of neighboring tubes) and a quasicontinuous energy Ez of relatively free motion parallel to the axis of the tubes. At low temperature, the particles occupy the lowest energy states, the focus of this study. The transverse energy attains a global minimum value (E_t=E_min) for radii near R_min=0.995 nm for H2 and 0.848 nm for ^4He. The density of states N(E) near the lowest energy is found to vary linearly above this threshold value. As a result, there occurs a Bose-Einstein condensation of the molecules into the channel with the lowest transverse energy. The transition is characterized approximately as that of a four dimensional gas, neglecting the interactions between the adsorbed particles. The phenomenon is observable, in principle, from a singular heat capacity.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MAR.W1003G