Helical multishell structures of magnesium nanowires

The structures of free-standing magnesium nanowires are systematically studied by using genetic algorithm simulations based on molecular dynamics with a tight-binding many body potential. Several helical multishell cylindrical growth sequences are observed for magnesium nanowires. The numbers of atomic strands show the even-odd or odd-even coupling between the inner and outershell with the differences of five strands, These multishell structures are made up of coaxial tubes in the three- and four-strands helical, centered pentagonal and hexagonal, and double-chain-core parallel curved surface epitaxy. The average binding energy and coordination numbers are calculated. The angular correlation functions and vibrational properties of magnesium nanowire have also been studied. (C) 2004 American Institute of Physics.