Absolute photoabsorption cross section of C60 in the extreme ultraviolet

The absolute photoabsorption cross section curve of C60 has been determined by means of mass spectrometry with the photon source of monochromatized synchrotron radiation of hν = 24.5-150 eV. Description has been made on a high-temperature source of gaseous fullerenes and an efficient time-of-flight mass spectrometer. The cross section was estimated by assuming an approximate expression of the number density of C60 in the ionization region. The resultant values were 762, 241, and 195 Mb at hν = 24.5, 90, and 110 eV, respectively, with about 10% errors. The cross section curve was then normalized at hν = 25 eV to the absolute photoabsorption cross section reported by Jaensch and Kamke [R. Jaensch, W. Kamke, Mol. Mater. 13 (2000) 143], the most reliable data so far available in the valence excitation region of C60. Accordingly, the present cross section data were altered to 407, 144, and 114 Mb at hν = 25, 90, and 110 eV, respectively.