Single-walled carbon nanotubes (SWNTs) are synthesized in a gas-phase non-equilibrium plasma process. The carbon producing CO disproportionation reaction is driven very efficiently in a flow reactor, in which extreme disequilibrium between the vibrational and translational mode of the carbon monoxide gas is maintained even at low translational temperatures by using a powerful and efficient carbon monoxide gas laser. In the presence of metal catalysts. the vibrationally excited CO reacts to form CO2 and structured carbon molecules, notably SWNTs. The individual tubes form ropes or flat ribbons and these are aligned parallel to each other into larger structures of SWNT material without any post-synthesis treatment. (C) 2002 Published by Elsevier Science B.V.