The luminescence from pseudo-isocyanine Langmuir-Blodgett films induced by the irradiation of charged particles with energy of the order of megaelectronvolts has been measured. The damaged cross-sections for the emission yield in the cases of H+ and He+ were determined and related to an effective coherent size of J aggregate. In addition to the fluorescence from the well-known excitonic states (J band) which had been observed with photo-excitation, a new band was found at lower frequencies in emission spectra. The experimental results indicate that the mobilities of the species responsible for this band are larger than those for the J band.