Absolute photoabsorption cross section of C 60 in the extreme ultraviolet

Abstract

The absolute photoabsorption cross section curve of C 60 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 C 60 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 C 60. Accordingly, the present cross section data were altered to 407, 144, and 114 Mb at hν = 25, 90, and 110 eV, respectively.