Photoabsorption cross section of C_(60) thin films from the visible to vacuum ultraviolet

摘要

Absolute photoabsorption cross sections of C_(60) thin films are determined in the hv range from 1.3 to 42 eV by using photon attenuation method. The spectrum shows a prominent peak of 1180 Mb at 22.1 eV with several fine structures due to single-electron excitation similarly to the case of C_(60) in the gas phase. The complex refractive index and complex dielectric function are calculated up to 42 eV through the Kramers-Kronig analyses. From the present data of C_(60) thin films the cross section curve of a molecular C_(60) is calculated with an assumption that the polarization effect of surrounding C_(60) molecules can be expressed by the standard Clausius-Mossotti relation. The spectrum thus obtained shows an excellent agreement with that of C_(60) in the gas phase measured independently.