The Raman intensity of the disorder-induced D-band in graphitic materials is calculated as a function of the in-plane size of the graphite nanoparticles (L-a) and as a function of the excitation laser energy. Matrix elements associated with the double resonance Raman processes, i.e., electron-photon, electron-phonon and electron-defect processes are calculated based on the tight binding method. The electron-defect interaction is calculated by considering the elastic scattering at the armchair edge of graphite, adopting a nanographite flake whose width is L-a. We compare the calculated results with the experimental results obtained from the spectra for different laser lines and L-a. (c) 2006 Elsevier B.V. All rights reserved.