Neutron inelastic scattering spectra from high quality single-wall carbon nanotubes (SWNTs), progressively dosed with hydrogen, have been measured with high resolution at different temperatures in the vicinity of 20 K. The spectra consist of two parts. Firstly, a relatively sharp complex peak, due to scattering from translationally bound molecules undergoing rotational transitions, is observed at around 14.5 meV. Secondly, there is a series of broad features at higher energies originating from roto-vibrational transitions corresponding to J = 0 to 1 rotational change plus n = 0 to n = 1, 2, etc molecular centreof- mass vibrational transitions, as well as frommolecule centre-of-mass recoil. The structure of the complex sharp peak suggests that the molecular hydrogen is adsorbed on at least two different adsorption sites on the surfaces of the nanotube bundles.
Hydrogen site occupancies in single-walled carbon nanotubes studied by inelastic neutron scattering
D Colognesi
2004
Abstract
Neutron inelastic scattering spectra from high quality single-wall carbon nanotubes (SWNTs), progressively dosed with hydrogen, have been measured with high resolution at different temperatures in the vicinity of 20 K. The spectra consist of two parts. Firstly, a relatively sharp complex peak, due to scattering from translationally bound molecules undergoing rotational transitions, is observed at around 14.5 meV. Secondly, there is a series of broad features at higher energies originating from roto-vibrational transitions corresponding to J = 0 to 1 rotational change plus n = 0 to n = 1, 2, etc molecular centreof- mass vibrational transitions, as well as frommolecule centre-of-mass recoil. The structure of the complex sharp peak suggests that the molecular hydrogen is adsorbed on at least two different adsorption sites on the surfaces of the nanotube bundles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
