26 research outputs found

    Разработка рекламной кампании промышленного предприятия и оценка ее эффективности (на примере ОАО «Коминтерн»)

    Get PDF
    Spectra of triply charged carbon disulphide have been obtained by measuring, in coincidence, all three electrons ejected in its formation by photoionization. Measurements of the CS23+ ion in coincidence with the three electrons identify the energy range where stable trications are formed. A sharp peak in this energy range is identified as the 2Π ground state at 53.1±0.1 eV, which is the lowest electronic state according to ab initio molecular orbital calculations. Triple ionization by the double Auger effect is provisionally divided, on the basis of the pattern of energy sharing between the two Auger electrons into contributions from direct and cascade Auger processes. The spectra from the direct double Auger effect via S 2p, S 2s, and C 1s hole states contain several resolved features and show selectivity based on the initial charge localization and on the identity of the initial state. Triple ionization spectra from single Auger decay of S 2p -based core-valence states CS22+ show retention of the valence holes in this Auger process. Related ion-electron coincidence measurements give the triple ionization yields and the breakdown patterns in triple photoionization at selected photon energies from 90 eV to above the inner shell edges

    Studies of Single and Multiple Ionization Processes in Rare Gases and some Small Molecules

    No full text
    In this thesis various aspects of photoionization are investigated with respect to both single and multiple electron emission from atoms and molecules. The studies include both valence and core levels and involve transitions which leave the atoms or molecules in various charge states. S2p electrons in the CS2 molecule were excited into Rydberg orbitals close to the ionization threshold. Subsequent autoionization leads to the emission of single electrons which were detected by a conventional electron spectrometer, bringing the molecule into various cationic states characterized by two valence holes and a Rydberg spectator electron. Vibrational progressions have been assigned as excitations of the totally symmetric v1 and the asymmetric stretching v3 modes in the cationic states. Double ionization spectra of the CS2 molecule were recorded in the S2p and C1s innershell ionization regions using a magnetic bottle many-electron coincidence spectrometer, revealing dicationic states formed out of one inner-shell vacancy and one vacancy in the valence region. The spectrum connected to the S2p vacancy is richly structured in contrast to the spectrum connected to the C1s vacancy, which shows essentially one distinct band. The development of a new variant of the magnetic bottle coincidence technique tailored for valence triple photoionization studies of rare gas atoms at synchrotron radiation sources is presented, overcoming the problem of high repetition rate in single-bunch operation of the storage ring. The studies of the rare gas atoms confirm that a correction of the lowest triple-ionization energy of Kr, currently listed in standard tables, is needed. Also, single-site N1s and O1s double core ionization of the NO and N2O molecules and single-site O1s, C1s and S2p double core ionization of the OCS molecule has been studied with the magnetic bottle technique. Double core holes are of particular interest due to putatively larger chemical shifts compared to single core holes. The observed ratio between the double and single ionization energies are in all cases close or equal to 2.20

    Studies of Single and Multiple Ionization Processes in Rare Gases and some Small Molecules

    No full text
    In this thesis various aspects of photoionization are investigated with respect to both single and multiple electron emission from atoms and molecules. The studies include both valence and core levels and involve transitions which leave the atoms or molecules in various charge states. S2p electrons in the CS2 molecule were excited into Rydberg orbitals close to the ionization threshold. Subsequent autoionization leads to the emission of single electrons which were detected by a conventional electron spectrometer, bringing the molecule into various cationic states characterized by two valence holes and a Rydberg spectator electron. Vibrational progressions have been assigned as excitations of the totally symmetric v1 and the asymmetric stretching v3 modes in the cationic states. Double ionization spectra of the CS2 molecule were recorded in the S2p and C1s innershell ionization regions using a magnetic bottle many-electron coincidence spectrometer, revealing dicationic states formed out of one inner-shell vacancy and one vacancy in the valence region. The spectrum connected to the S2p vacancy is richly structured in contrast to the spectrum connected to the C1s vacancy, which shows essentially one distinct band. The development of a new variant of the magnetic bottle coincidence technique tailored for valence triple photoionization studies of rare gas atoms at synchrotron radiation sources is presented, overcoming the problem of high repetition rate in single-bunch operation of the storage ring. The studies of the rare gas atoms confirm that a correction of the lowest triple-ionization energy of Kr, currently listed in standard tables, is needed. Also, single-site N1s and O1s double core ionization of the NO and N2O molecules and single-site O1s, C1s and S2p double core ionization of the OCS molecule has been studied with the magnetic bottle technique. Double core holes are of particular interest due to putatively larger chemical shifts compared to single core holes. The observed ratio between the double and single ionization energies are in all cases close or equal to 2.20

    Studies of Single and Multiple Ionization Processes in Rare Gases and some Small Molecules

    No full text
    In this thesis various aspects of photoionization are investigated with respect to both single and multiple electron emission from atoms and molecules. The studies include both valence and core levels and involve transitions which leave the atoms or molecules in various charge states. S2p electrons in the CS2 molecule were excited into Rydberg orbitals close to the ionization threshold. Subsequent autoionization leads to the emission of single electrons which were detected by a conventional electron spectrometer, bringing the molecule into various cationic states characterized by two valence holes and a Rydberg spectator electron. Vibrational progressions have been assigned as excitations of the totally symmetric v1 and the asymmetric stretching v3 modes in the cationic states. Double ionization spectra of the CS2 molecule were recorded in the S2p and C1s innershell ionization regions using a magnetic bottle many-electron coincidence spectrometer, revealing dicationic states formed out of one inner-shell vacancy and one vacancy in the valence region. The spectrum connected to the S2p vacancy is richly structured in contrast to the spectrum connected to the C1s vacancy, which shows essentially one distinct band. The development of a new variant of the magnetic bottle coincidence technique tailored for valence triple photoionization studies of rare gas atoms at synchrotron radiation sources is presented, overcoming the problem of high repetition rate in single-bunch operation of the storage ring. The studies of the rare gas atoms confirm that a correction of the lowest triple-ionization energy of Kr, currently listed in standard tables, is needed. Also, single-site N1s and O1s double core ionization of the NO and N2O molecules and single-site O1s, C1s and S2p double core ionization of the OCS molecule has been studied with the magnetic bottle technique. Double core holes are of particular interest due to putatively larger chemical shifts compared to single core holes. The observed ratio between the double and single ionization energies are in all cases close or equal to 2.20

    Double ionization of atomic cadmium

    No full text
    We have recorded the double photoionization spectrum of atomic Cd at four different photon energies in the range 40-200 eV. The main channel is single ionization and subsequent decay of excited Cd+ states, some involving Coster-Kronig processes, whereas direct double ionization is found to be weak. The decay of the excited Cd+ states shows a strong selectivity, related to the configuration of the final state. Double ionization leading to the Cd2+ ground state is investigated in some detail and is found to proceed mainly through ionization and decay of 4d correlation satellites. The most prominent autoionization peaks have been identified with the aid of quantum-mechanical calculations

    Double ionization of atomic cadmium

    No full text
    We have recorded the double photoionization spectrum of atomic Cd at four different photon energies in the range 40-200 eV. The main channel is single ionization and subsequent decay of excited Cd+ states, some involving Coster-Kronig processes, whereas direct double ionization is found to be weak. The decay of the excited Cd+ states shows a strong selectivity, related to the configuration of the final state. Double ionization leading to the Cd2+ ground state is investigated in some detail and is found to proceed mainly through ionization and decay of 4d correlation satellites. The most prominent autoionization peaks have been identified with the aid of quantum-mechanical calculations

    Triple ionization spectra by coincidence measurements of double Auger decay : The case of OCS

    No full text
    By combining multiple electron coincidence detection with ionization by synchrotron radiation, we have obtained resolved spectra of the OCS3+ ion created through the double Auger effect. The form of the spectra depends critically on the identity of the atom bearing the initial hole. High and intermediate level electron structure calculations lead to an assignment of the resolved spectrum from ionization via the S 2p hole. From the analysis it appears that the double Auger effect from closed shell molecules favors formation of doublet states over quartet states. Molecular field effects in the double Auger effect are similar to those in the single Auger effect in linear molecules

    Triple ionisation of methane by double Auger and related pathways

    No full text
    Triple ionisation of methane by decay of the singly charged ion with a 1s vacancy produces a trication spectrum starting near 70 eV binding energy. Vibrational excitation in the initial hole state broadens and shifts the triple ionisation bands. Ionisation through core-valence doubly ionised states gives lower triple ionisation onsets and changes the spectral intensity pattern in accordance with retention of the initial valence holes in course of the double Auger effect. The double Auger effects occur both directly and as cascades, the different pathways producing different electron distributions and final state spectra. (C) 2009 Elsevier B. V. All rights reserved

    Triple ionisation of methane by double Auger and related pathways

    No full text
    Triple ionisation of methane by decay of the singly charged ion with a 1s vacancy produces a trication spectrum starting near 70 eV binding energy. Vibrational excitation in the initial hole state broadens and shifts the triple ionisation bands. Ionisation through core-valence doubly ionised states gives lower triple ionisation onsets and changes the spectral intensity pattern in accordance with retention of the initial valence holes in course of the double Auger effect. The double Auger effects occur both directly and as cascades, the different pathways producing different electron distributions and final state spectra. (C) 2009 Elsevier B. V. All rights reserved

    Symmetry breaking in core-valence double photoionization of SO2

    No full text
    Core-valence double photoionization electron spectra of the SO2 molecule involving the S 2p and O 1s inner shells have been measured using a time-of-flight multiparticle coincidence technique. The experimental spectra are compared with quantum-chemical calculations based on density functional theory by which several core-valence dicationic states are identified. Assignments conform with a picture where the formation of a O 1s-valence dicationic state is associated with a physical, "pseudo-Jahn-Teller," symmetry breaking and core-hole localization. It is shown that while density functional theory gives very good transition energies in the symmetry-broken case, it gives a poor representation in the symmetry-restricted case, and an incomplete account of the Hartree-Fock localization energy
    corecore