title: Nonstoichiometric intensities in core photoelectron spectroscopy.
abstract: X-ray photoemission spectroscopy is used in a great variety of research fields; one observable is the sample's stoichiometry. The stoichiometry can be deduced based on the expectation that the ionization cross sections for innershell orbitals are independent of the molecular composition. Here we used chlorine-substituted ethanes in the gas phase to investigate the apparent carbon stoichiometry. We observe a nonstoichiometric ratio for a wide range of photon energies, the ratio exhibits x-ray-absorption fine structure spectroscopy (EXAFS)-like oscillations and hundreds of eV above the C1s ionization approaches a value far from 1. These effects can be accounted for by considering the scattering of the outgoing photoelectron, which we model by multiple-scattering EXAFS calculations, and by considering the effects of losses due to monopole shakeup and shakeoff and to intramolecular inelastic scattering processes.
authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Söderström
authors.forename: N
authors.initials: N
authors.lastname: Mårtensson
authors.forename: O
authors.initials: O
authors.lastname: Travnikova
authors.forename: M
authors.initials: M
authors.lastname: Patanen
authors.forename: C
authors.initials: C
authors.lastname: Miron
authors.forename: L J
authors.initials: LJ
authors.lastname: Sæthre
authors.forename: K J
authors.initials: KJ
authors.lastname: Børve
authors.forename: J J
authors.initials: JJ
authors.lastname: Rehr
authors.forename: J J
authors.initials: JJ
authors.lastname: Kas
authors.forename: F D
authors.initials: FD
authors.lastname: Vila
authors.forename: T D
authors.initials: TD
authors.lastname: Thomas
authors.forename: S
authors.initials: S
authors.lastname: Svensson