Characterization of C₆₀ Films Polymerized by Ion Irradiation

Abstract

Polymerization of C₆₀ thin films by 7‐MeV C²⁺ ion irradiation is studied with Raman spectroscopy and X‐ray diffraction (XRD). Raman analysis reveals that polymerization of the C₆₀ molecules that have survived destruction by ion bombardment proceeds with further irradiation; after irradiation with 1×10¹⁶/cm², most of the surviving molecules have been polymerized. XRD analysis shows that reflection angles of 111 and 222 in an fcc crystal of C₆₀ shift to higher angles with the increasing ion fluence. This is due to the contraction of the intermolecular distance induced by the polymerization and the contraction amounts to ∼4% after the irradiation with 1×10¹⁶/cm².

Keywords:

• C₆₀
• ion irradiation
• C₆₀ polymer
• Raman spectroscopy
• X‐ray diffraction analysis

Acknowledgment

The authors are grateful to the crew of the 3‐MV Tandem accelerator of JAERI/Takasaki.