EVIDENCE FOR OSCILLATIONS IN THE C-70 VALENCE PHOTOIONIZATION CROSS-SECTIONS

Photoelectron spectra of molecular C-70 were recorded in the photon en ergy range from 20 to 60 eV to investigate the photoionization cross s ection behavior of the outermost molecular orbitals. As in the case of C-60, these photolines exhibit photon energy-dependent intensity osci llations, thus corroborating a quantum oscillation model based on the fullerene's unique shape. The photoelectron angular distribution param eter beta measured during the same experiment shows, similarly to C-60 , no pronounced oscillations, rather rising continuously as the photon energy is increased, a fullerene-unspecific behavior also known from other carbon-containing molecules, such as CO. (C) 1997 Elsevier Scien ce B.V.