Production of jet-cooled coronene and coronene cluster anions and their study with photoelectron spectroscopy

Anions of coronene (C24H12) and its clusters are produced by laser ablation of a pressed pellet sample in a double rod, pulsed nozzle source. Coronene anions are produced efficiently only when transition metal vapor is presen t in the same plasma from co-vaporization of a metal sample. Anion monomers and clusters of coronene are size-selected and studied with photoelectron spectroscopy in a magnetic bottle spectrometer. Spectra at 532, 355 and 266 nm probe electron affinities and neutral electronic states. The electron a ffinity of coronene is 0.47 +/- 0.09 eV and that of coronene dimer is 0.67 +/- 0.09 eV. (C) 1999 Elsevier Science B.V. All rights reserved.