Gas phase electronic spectrum of the nitrogen terminated nanowire NC16N

The UV electronic spectrum of NC16N has been measured by means of a mass selective resonant two-color two-photon ionization technique. The observed bands are assigned to the dipole allowed, B(1)Sigma(u)(+) <-- X(1)Sigma(g)(+), electronic transition. The electronic structures of NC2nN (n = 2-8) in the ground and excited states have been investigated using density functional theory. The calculated transition energies of the A(1)Delta(u)((1)Sigma(u)(-)) <-- X(1)Sigma(g)(+) and the B(1)Sigma(u)(+) <-- X(1)Sigma(g)(+) systems decrease monotonically with increasing chain size and slowly converge to the HOMO-LUMO gap of the long chain limit. The present studies imply that a long carbon nanowire terminated with nitrogen will be! semiconducting due to pi-electron localization and bond-length alternation. (C) 2004 Elsevier B.V. All rights reserved.