Core photoionization of the argon dimer in the photon-energy range of 255–340 eV studied by a photoelectron-photoion-photoion coincidence technique

Abstract

Single-photon multiple ionization of the argon dimer van der Waals complex, ${\mathrm{Ar}}_{2}$, is studied by the photoelectron-photoion-photoion coincidence technique using synchrotron radiation in the photon-energy range of 255--340 eV, which covers the Ar 2$p$ and Ar 2$s$ ionization continua. Dissociation processes into ${\mathrm{Ar}}^{+}+{\mathrm{Ar}}^{+}$, ${\mathrm{Ar}}^{+}+{\mathrm{Ar}}^{2+}$, ${\mathrm{Ar}}^{+}+{\mathrm{Ar}}^{3+}$, and ${\mathrm{Ar}}^{2+}+{\mathrm{Ar}}^{2+}$ ion pair channels are observed. The ${\mathrm{Ar}}^{+}+{\mathrm{Ar}}^{+}$ and ${\mathrm{Ar}}^{+}+{\mathrm{Ar}}^{2+}$ channels show the most intense ion-ion coincidences, compared to other observed dissociative channels. For the four observed channels the intensities are integrated and compared as functions of photon energy.