Coster-Kronig Spectra Research Articles

The N4,5 - OO Auger and “N3” N4,5O2,3 Coster-Kronig spectra of xenon induced by electron impact

The N4,5OO Auger electron spectrum in the kinetic energy region (14–37) eV has been measured with high resolution at electron incident energies between 71 eV and 2019 eV. The Auger and satellite lines are assigned by comparison with previous literature data. Several states which correspond to the resonant Auger transitions from the 4d3/2, 5/2 6p states are observed. The PCI effects on the N5-O2,3O2,3(1S0) Auger peak when the incident electron energy approaches to the N5 edge (67.55 eV) is investigated and it is found that the dependence of the energy shift on the excess energy, Eexc, is well represented by the function Eexcβ with β = (-1.40 ± 0.05). The “N3” N4,5O2,3 Coster-Kronig spectrum is measured at various electron incident energies. The assignments of the features are made in comparison with a similar spectrum from synchrotron radiation measured by Kivimäki et al. [J. Electron Spectrosc. Relat. Phenom. 1999, 101–103, 43–47]. The Auger spectrum in the kinetic energy regions (68–78) eV and (90–138) eV is observed for the first time in an electron impact experiment and a comparison is made with the photoionization experiment by Hikosaka et al. [Phys. Rev. A 2007, 76, 032708].

The M4,5-NN Auger and M2,3-M4,5N Coster-Kronig spectra of krypton induced by electron impact

The Kr M4,5-NN Auger transitions are studied in the kinetic energy region 24 - 59 eV by using non-monochromatic electron beam and a high resolution electrostatic analyzer. Among the sixty four features observed, fifty five are assigned, while nine stay unassigned. The post-collision interaction (PCI) effects in the M5-N1N1(1S0) and M5-N2,3N2,3(1S0) Auger peaks are studied as a function of electron incident energy approaching the M5 edge (95.04 eV). The PCI shifts are found to be well represented by an exponential function of the excess energy with exponents β = (-0.99±0.05 and -3.08±0.05) for the N2,3N2,3(1S0) and N1N1(1S0) peaks, respectively. The M2,3-M4,5N Coster-Kronig transitions are studied in kinetic energy region 65 - 110 eV and at incident energies from 120 to 2019 eV. Owing to a high resolution twelve well resolved satellites in the region bellow 90 eV are observed, while in the region 90 - 110 eV two broad features are assigned to the M2,3-M4,5N2,3 C-K peaks with intensity ratio (M3/M2 = 2.37) are observed. Comparison is made with available data from literature.

Auger decay of 4d inner-shell holes in atomic Hg leading to triple ionization

Formation of triply ionized states upon the creation of $4d$ inner-shell holes in atomic Hg is investigated by using synchrotron radiation of 730 eV photon energy and a versatile multielectron coincidence detection technique in combination with multiconfiguration Dirac-Fock calculations. By carefully selecting Coster-Kronig electrons detected only in coincidence with a $4d$ photoelectron, the Coster-Kronig spectrum has been extracted and the corresponding branching ratios of the $4d$ hole have been determined. The results are found to differ from previously established experimental ratios based on electron impact ionization but to agree now better with theory. We also present an Auger cascade analysis of pathways leading to triply ionized states of atomic Hg upon removal of a $4d$ inner-shell electron.

MVV super Coster–Kronig spectra of nickel near the excitation threshold

The MVV super Coster–Kronig (sCK) spectra of metallic Ni have been measurednear the 3p excitation threshold by varying excitation photon energy. The resultshave been interpreted on the basis of the Cini–Sawatzky theory. The measuredsCK band has composite structure with features at electron kinetic energy of49.8, 56.3, 59.5, and 60.5 eV. If we interpret the band at 49.8 eV to be the split-offquasi-atomic band, we can estimate the effective intra-atomic Coulomb energy ata large value of 8 eV. The spectral shape of the MVV sCK band measured byexcitation with vacuum ultraviolet light does not coincide with that obtained by theMg K α excitation orwith that of the L3VV Coster–Kronig band. The shape of the MVV sCK spectrum changes as excitation energychanges. The excitation-energy range in which such spectral change occurs extends fromthe 3p threshold to 10 eV above it. As the kinetic energy for the MVV sCK band starts tooverlap that of the two-hole-bound-state band, the MVV sCK band changes its shapeconsiderably and the two spectra become inseparable. In this excitation-energy region, thespectator electron excited optically forms a virtual bound state with the two 3d holes. Thelocation of the apparent two-hole-bound-state band shifts toward high binding energy onthe 3p–3d resonance. This can be interpreted as a kind of final state interaction. Thesuggested intermediate and final states of the single-step transition are consistent withthe constant-initial-state spectra and total photoyield spectrum. The roles ofthe screening by conduction electrons and the sd hybridization are emphasized.

Lifetime and Auger decay of strongly correlated 4p hole states of xenon

The xenon 4p photoelectron spectrum and the subsequent 4p −1→(5s,5p) −2 Auger and 4p −1→4d −1(5s,5p) −1 Coster–Kronig spectra have been studied with the aid of a high-resolution experiment and multiconfigurational Dirac–Fock calculations. Strong electron correlation is known to affect drastically the Xe 4p photoelectron spectrum: the 4p 1/2 component disappears completely, and the intensity of the 4p 3/2 line is redistributed into several close-lying peaks. We have calculated the lifetime widths of the photoelectron peaks, simulated the observed photoelectron and Auger spectra and compared theoretical results with experiment.

Lifetime and Auger decay of strongly correlated 4p hole states of xenon

The xenon 4p photoelectron spectrum and the subsequent 4p−1→(5s,5p)−2 Auger and 4p−1→4d−1(5s,5p)−1 Coster–Kronig spectra have been studied with the aid of a high-resolution experiment and multiconfigurational Dirac–Fock calculations. Strong electron correlation is known to affect drastically the Xe 4p photoelectron spectrum: the 4p1/2 component disappears completely, and the intensity of the 4p3/2 line is redistributed into several close-lying peaks. We have calculated the lifetime widths of the photoelectron peaks, simulated the observed photoelectron and Auger spectra and compared theoretical results with experiment.

L1−L2,3MCoster-Kronig transitions in argon

The ${L}_{1}\ensuremath{-}{L}_{2,3}M$ Coster-Kronig spectrum of argon has been measured by using photon excitation. The intensity ratio of $0.30\ifmmode\pm\else\textpm\fi{}0.02$ between the ${L}_{1}\ensuremath{-}{L}_{2,3}{M}_{1}$ main lines and the ${L}_{1}\ensuremath{-}{L}_{2,3}{M}_{2,3}$ lines is extracted from experiment. The experimental results for the ratio and partial decay rates are compared with present and previous theoretical estimates.

Interpretation of the N2,3N4,5O2,3 Coster–Kronig spectrum of xenon

Abstract The N 2,3 N 4,5 O 2,3 Coster–Kronig spectrum of Xe has been measured with synchrotron radiation. It arises from the decay of the 4 p core hole states that are split by strong configuration interaction to numerous close-lying components. Their binding energies are obtained from a high-resolution 4 p photoelectron measurement. The interpretation of the Coster–Kronig spectrum is further hampered by the lack of accurate binding energies for the 4 d −1 5 p −1 final states. The latter are, however, also reached in the M 4 , 5 N 4 , 5 O 2 , 3 Auger spectrum which has been measured in this work with electron impact ionization and assigned with the aid of calculations. With this new information the N 2 , 3 N 4 , 5 O 2 , 3 Coster–Kronig spectrum can be interpreted semi-empirically. It is also compared with calculations.

The L Auger spectra of 64155Gd, 65159Tb, 67165Ho and 70171Yb from radioactive decay

The L Auger spectra of 155Gd, 159Tb, 165Ho and 171Yb resulting from radioactive decay were analysed at an instrumental resolution of 7 and/or 12 eV by means of an electrostatic spectrometer. The L 3 M 4,5 M 4,5 line groups of 167Er and 169Tm were also measured. The energies and relative intensities of about 50–70 L Auger lines or line groups were determined for each spectrum. With the exception of 155Gd, the measured absolute energies of the dominant L 3 M 4 M 5 lines were higher by about 21 eV than those expected from the semi-empirical calculations of Larkins. Relative intensities of non-relativistic calculations in jj coupling by McGuire were found to be in reasonable agreement with the measurements. Intermediate coupling splittings predicted by Larkins for the L 3 M 4,5 M 5 lines were observed in all studied spectra. Intense “spectator vacancy” satellites were seen in L 3 MM Auger spectra of 169Tm and 171Yb. The L Coster—Kronig spectra of 159Tb, 160Ho and 169Tm were also measured, although no detailed analysis was made.

M-shell Coster-Kronig electron spectra of germane

Coster-Kronig spectra for M-shell holes produced by electron impact have been measured for germane in the kinetic energy range 25–100 eV. M 2,3M 4,5M 4,5 super-Coster-Kronig transitions were identified by comparison with the L 2,3M 4,5M 4,5 Auger spect and represent the main decay channel. The assigned M 2,3M 4,5N 2,3 Coster-Kronig transitions exhibit a strong satellite spectrum, probably due to the decay of a doubly ionized M 2,3 initial state originated from M 1M 2,3N 2,3 Coster-Kronig processes. Low-intensity structures centered at about 93.5 eV have been assigned to a M 1M 4,5M 4,5 super-Coster-Kronig transition.

Auger electron spectra of gaseous halogen compounds

Abstract Auger CW and Coster-Kronig spectra in gas phase of boron trifluoride, boron trichloride, boron tribromide and hydrogen bromide have been obtained by 2 keV electron impact. The fluorine spectrum can be understood as quasi-atomic by the Thomas—Weightman Δ U/W criterion, while in the spectra of the heavier halides some of the final states are delocalized. The boron spectrum from boron trifluoride is definitely band-like, but it also shows two prominent quasi-atomic structures induced by fluorine. A simplified model allows the nature of these “partner resonances” to be understood and their intensities calculated; a semi-quantitative agreement with experiment is obtained without adjustable parameters. We provide evidence that these resonances are a general feature of the CW spectra of ionic molecules and identify them in the boron spectrum, from boron tribromide, as well as in the literature data.

L1−L23M1Coster-Kronig spectrum of argon in intermediate coupling

Transition energies and rates in the ${L}_{1}\ensuremath{-}{L}_{23}{M}_{1}$ Coster-Kronig spectrum of argon have been calculated in the intermediate-coupling scheme. Strong mixing of the final ionic states $^{1}P_{1}$ and $^{3}P_{1}$, caused by the spinorbit interaction, virtually removes the large discrepancy between previously calculated relative term intensities and experimental data. Transition energies also agree well.

Theoretical investigations of the L1-L23M Coster-Kronig spectrum of argon

Investigations of the ArL1-L23M Coster-Kronig spectrum have been undertaken from a theoretical standpoint, with a view to gaining some insight into the effects which must be included in calculations of Coster-Kronig spectra. The areas of investigation were: energies of states with two open subshells of the same symmetry and occupation number; the effect of electron correlation on energies and rates of transitions where the final state has a valence shell s hole; the dependence of the individual rates on electron energy and the dependence of the L1-L23M1 rates on the Coulomb potential of the residual ion as a function of energy. It is concluded that fairly elaborate calculations which account for all the effects described must be done in order to obtain accurate Coster-Kronig energies and rates.

Low-energy Coster—Kronig spectra of atomic and metallic manganese

Low-energy Coster—Kronig spectra have been measured for manganese vapour and metal using 3-keV electron-beam excitation. The L 2 L 3 M 4,5 transitions have been observed only in the metal phase. 3 p → 3 d excitation seems to precede in both phases the M 2,3 M 4,5 M 4,5 transitions, leading to 3 d autoionization-type transitions which dominate over diagram Coster—Kronig lines.

L-shell Auger and Coster-Kronig spectra from relativistic theory

The intensities of L-shell Auger and Coster-Kronig transitions in heavy atoms have been calculated relativistically. A detailed comparison is made with measured Auger spectra of Pt and U. The pertinent transition energies were computed from relativistic wave functions with inclusion of the Breit interaction, self-energy, a vacuum-polarization correction, and complete atomic relaxation. Multiplet splitting is found to distribute Auger electrons from certain transitions among several lines. The analysis leads to reassignment of a number of lines in the measured spectra. Lines originally identified as L2-L3Ni in the U spectrum are shown to arise from M4,5 Auger transitions instead.

L-Shell Auger and Coster-Kronig Electron Spectra

Individual-term electron transition rates for initial $L$-shell holes are presented in $j\ensuremath{-}j$ coupling. Comparison with experimental-term intensities are made for platinum, tellurium, uranium, argon, and krypton. For the latter two elements agreement is poor. Comparison with experiment indicates some prominent peaks in the uranium ${L}_{2}$ Coster-Kronig spectrum are improperly identified.

Auger- und Coster-Kronig-�berg�nge der M-Schale von Krypton

The Auger spectra of theM 2,M 3,M 4,M 5 subshells of krypton and the Coster-Kronig spectra of theM 1,M 2,M 3 subshells of krypton were measured with an electrostatical spectrometer. The ionization in theM shells was caused by electron impact. The use of a gaseous target made it possible to measure the Auger lines even at energies as low as 25 eV. The absolute energies and relative intensities of a great number of transitions were determined: 22 of theM 4, 5 spectrum, 14 of theM 2, 3 spectrum and 2 of theM 1 spectrum. Only in the case of theM 2, 3 spectrum a comparison between the relative intensities, determined experimentally, and those calculated byRubenstein forZ=47 was possible. The agreement is only qualitatively. Moreover, from the Auger electron energies measured, the following binding energies were calculated:E(M 1)=(292,1±1,0) eV,E(M 2)=(222,1±0,6) eV,E(M 3)=(214,6±0,6)eV,E(N 1 N 1)=(62,81±0,05) eV.