We perform Raman investigation on two different samples of single-wall carbon nanotube (SWNTs). The first sample (S1) contains a majority of thick bundles, and the second sample (S2) only contains thin bundles and/or isolated SWNT. Our Raman study reports experimental evidences on the vanishing of the Breit-Wigner-Fano (BWF) resonance when the size of the bundle decreases. (C) 2003 Elsevier Science B.V. All rights reserved.