Abstract: Self-assembled film of C₆₀ with ethylene diamine as intermolecular string were analyzed by the method of laser time-of-flight mass spectrometry. Similar mass spectra were found for self assembled monolayer film of C₆₀ on glass or silicon surface. For the glass film, the highest ion was C₁₁₂⁺, while for silicon film was C₁₀₂⁺. When n >32, the fragmentation of C_n showed the lost of two carbon atoms each time. And the adduct(C₆₀ + ethylene diamine) wasn't found in the spectra. It was assumed that at such a condition only C₆₀ and its dimer are desorbed. The reason was that the bond between ethylene diamine and the surface of glass or silicon were stronger than that between ethylene diamine and C₆₀. The spectra of self assembled dilayer film of C₆₀ was different from that of monolayer film. In the spectra of dilayer film, when m/z <600, few peaks were found; when 600< m/z <720, the spectra had the characteristic fragmentary spectra of pure C₆₀; when m/z >720, there was a broad peak. The above results demonstrated that laser MScan provide useful structural information in the study of fullerene film.

Key words: C₆₀, Ethylene diamine, Self-assembled film of C₆₀, Laser mass spectrometry