Many-electron systems confined to a quasi-1D geometry by a cylindrical distribution of positive charge have been investigated by density functional computations in the unrestricted local spin density approximation. Our investigations have been focused on the low density regime, in which electrons are localised. The results reveal a wide variety of different charge and spin configurations, including linear and zig-zag chains, single and double-strand helices, and twisted chains of dimers. The spin-spin coupling turns from weakly anti-ferromagnetic at relatively high density, to weakly ferromagnetic at the lowest densities considered in our computations. The stability of linear chains of localised charge has been investigated by analysing the radial dependence of the self-consistent potential and by computing the dispersion relation of low-energy harmonic excitations.
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