title: Experimental observation of single-file water filling of thin single-wall carbon nanotubes down to chiral index (5,3).
abstract: Single-file transport of water into carbon nanotubes is experimentally demonstrated for the first time through the splitting of the radial breathing mode (RBM) vibration in Raman spectra of bile salt solubilized tubes when both empty (closed) and water-filled (open-ended) tubes are present. D2O filling is observed for a wide range of diameters, d, down to very thin tubes [e.g., (5,3) tube, d=0.548  nm] for which only a single water molecule fits in the cross section of the internal nanotube channel. The shift in RBM frequency upon filling is found to display a very complex dependence on nanotube diameter and chirality, in support of a different yet well-defined ordering and orientation of water molecules at room temperature. Large shifts of the electronic transitions are also observed.
authors.affiliation: Physics Department, University of Antwerp (Campus Drie Eiken), Universiteitsplein 1, B-2610, Antwerp, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Cambré
authors.forename: Bob
authors.initials: B
authors.lastname: Schoeters
authors.forename: Sten
authors.initials: S
authors.lastname: Luyckx
authors.forename: Etienne
authors.initials: E
authors.lastname: Goovaerts
authors.forename: Wim
authors.initials: W
authors.lastname: Wenseleers