Defect formation in C60 molecules under irradiations with electrons and γ-ray

Defect formation, polymerization and resulting amorphization in C60 under irradiations with electrons and γ-ray were studied by micro-Raman spectroscopy. In the case of electron irradiation, amorphization was induced through accumulation of defects and/or polymerization. Under the electron irradiation above 150 keV, the effect of atomic displacement was evident for amorphization. On the other hand, below 150 keV, the electronic excitation induces amorphization through polymerization. In the case of γ-ray irradiation, polymerization was mainly introduced within the experimental conditions. Although the amorphization was not detected under γ-ray irradiation, the result of Raman spectroscopy indicated that bond opening in intramolecular C-C bondings partially occurred implying the preservation of its spherical shape. (author)