title: Interactions of anions and cations in carbon nanotubes.
abstract: We consider the insertion of alkali-halide ion pairs into a narrow (5,5) carbon nanotube. In all cases considered, the insertion of a dimer is only slightly exothermic. While the image charge induced on the surface of the tube favors insertion, it simultaneously weakens the Coulomb attraction between the two ions. In addition, the anion experiences a sizable Pauli repulsion. For a one dimensional chain of NaCl embedded in the tube the most favorable position for the anion is at the center, and for the cation near the wall. The phonon spectrum of such chains shows both an acoustic and an optical branch.
authors.affiliation: Institute of Theoretical Chemistry, Ulm University, Germany. wolfgang.schmickler@uni-ulm.de and PRELINE, FIQ, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: L
authors.initials: L
authors.lastname: Mohammadzadeh
authors.affiliation: PRELINE, FIQ, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: P
authors.initials: P
authors.lastname: Quaino
authors.affiliation: Institute of Theoretical Chemistry, Ulm University, Germany. wolfgang.schmickler@uni-ulm.de.
authors.forename: W
authors.initials: W
authors.lastname: Schmickler