Diagram Lines Research Articles

DoubleK-shell ionization of Al induced by photon and electron impact

This paper reports on the investigation of the double $K$-shell ionization of metallic aluminum induced by photon and electron impact. The experimental method consisted to measure the $K\ensuremath{\alpha}$ hypersatellite spectra resulting from the radiative decay of double $1s$ vacancy states by means of high-resolution x-ray spectroscopy using a Bragg-type von Hamos crystal spectrometer. Measurements of the photon-induced spectra were carried out at the European Synchrotron Radiation Facility, Grenoble, France, while those of the electron-induced spectra were performed at the University of Fribourg. The double $1s$ ionization probabilities and cross sections were derived from the $K{\ensuremath{\alpha}}_{2}$ hypersatellite to diagram line intensity ratios for photon beam energies ranging between 3.1 and 5.5 keV and for different incident electron-beam energies ranging between 4 and 20 keV. The energy and linewidth of the $K{\ensuremath{\alpha}}_{2}$ hypersatellite x-ray line were also determined for which consistent results were obtained from the photon and electron-beam measurements.

Evolution of satellite lines

AbstractEvolution of the photoionized KLL Auger satellite line for 3d transition metals was studied. The intensity ratio of the satellite line relative to the main 1D2 (KL2L3) diagram line was measured for Cu and Ni as a function of incident photon energy and the theoretical models based on the adiabatic approximation were fitted to the experimental data. The Thomas model, the Vatai model and the model of Roy et al. were considered. In addition, we modified the model of Roy et al. and developed a new model. Comparison of these four models was made and their difference was discussed. Copyright © 2009 John Wiley & Sons, Ltd.

Energies and relative intensities of K α3 and K α4 X-ray satellites of phosphorous by photon excitation

Energies and relative intensities of the K X-ray satellites K α4 and K α3 of phosphorous and three of its compounds (NH 4) 2HPO 4, Na 2HPO 4 and BaHPO 4 were measured by a wavelength dispersive spectrometer. The energy shifts of these satellites relative to the diagram line are compared with Dirac–Fock theoretical values. The energy shifts and relative intensities are examined for chemical effects.

Glass transition temperature-temperature-property (TgTP) diagram for EPY epoxy system

Evolution of storage and loss moduli during conversion progress of the filled epoxy system EPY® (Epidian 6 with triethylenetetramine), applied for the production of machine foundation chocks, was studied using dynamic mechanical thermal analysis (DMTA). The results obtained and the results previously reached by differential scanning calorimetry (DSC) and rotational viscometry made possible to determine the diagram glass transition temperature-temperature-property (TgTP) for the investigated system, where Tg is the direct measure of conversion and P denotes property under investigation - loss modulus. This way of using Tg in this diagram makes possible the linearization of the relationships among the temperatures corresponding to the maxima and minima of the physical properties and the extent of cure. The lines within TgTP diagram show the courses of structural transformations during cure i.e. glass transition (Tg), β-transition (Tβ) and gelation ( gel T g ). The diagram lines separate several regions which are dependent on the extent of cure and the material shows different physical properties within each of them. TgTP diagram calculated for the EPY® material can facilitate understanding of the relationships among transitions and material properties.

Kα X-ray satellite spectra of Ti, V, Cr and Mn induced by photons

K X-ray emission spectra of Ti, V, Cr and Mn generated by photon excitation have been studied with a crystal spectrometer. The measured energy shifts of Kα satellite relative to the diagram line are compared with values obtained by electron excitation and with different theoretical estimates. The present experimental values of KαL1/KαL0 relative intensities are compared with values obtained by electron excitation.

High-resolution KLM Auger spectra of Ni metal excited by X-rays

KLM Auger spectra of Ni metal were measured with high energy resolution and high statistical accuracy using monochromatic synchrotron radiation. The spectra were corrected for the background from inelastically scattered electrons using partial intensity analysis where the electron trajectories were calculated by Monte Carlo simulation. Following background correction, the corrected spectra were fitted to model peaks taking into account intrinsic excitations. The measured transition energy of the most intense KL 2M 3 ( 1D 2) Auger line is 7388.1 eV (0.4). The obtained relative intensities and energies of the Auger diagram lines are compared to published calculations as well as to experimental data for other 3d transition metals. In addition, the presence of Ni 3s, 3p photoelectron peaks in the spectra excited internally by Ni Kα X-rays is shown.

Energies and relative intensities of Kα3 and Kα4 x‐ray satellites of sulfur and sulfides by photon excitation

AbstractEnergies and relative intensities of the K x‐ray satellites Kα4 and Kα3 of sulfur and two sulfides K2S and FeS are measured by a wavelength dispersive spectrometer. The energy shifts of these satellites relative to the diagram line are compared with Dirac–Fock theoretical values. The energy shifts and relative intensities are examined for chemical effects. Supplementing the present data to the available data, Z dependence of Kα4/Kα3 intensity ratio is studied in the low Z region. Copyright © 2007 John Wiley & Sons, Ltd.

A high resolution X-ray crystal spectrometer to study electron and heavy-ion impact atomic collisions

We have studied fast ion-atom and electron-atom collision processes using a reconditioned high resolution X-ray spectrometer. The X-rays, generated by the collisions, are dispersed by a curved ADP crystal (Johansson geometry) and detected by a gas proportional counter. A self-written LabVIEW based program has been used to give precise and controlled movement to the crystal and for data acquisition. The performance was tested by detecting the Kα diagram and satellite lines of several elements. The Kα satellite lines of Al have been studied in collision with 3–12 keV electrons and 40 MeV C4+ ions. In ion collisions as large as four L-vacancies are created simultaneously with the K-vacancy, compared to two satellites in case of the e-impact. In addition, we have measured the X-rays from H-, He- and Li-like Si ions which arise due to the electron loss/capture process in highly charged 80 MeV Si7+ ions in collision with thin carbon foil. Approximate charge state distribution has been obtained using this new technique.

Satellites hidden by diagram lines in heavy elements Ir, Pt, Au

Hidden satellites due to Coster–Kronig transitions have a characteristic threshold energy in their appearance and hence can be identified by looking at spectra at either side of the threshold. To investigate the hidden satellites, we measured Lβ2,3,15 spectra of Ir, Pt and Au below and above the L1 edge. The measured spectra were normalized using Lβ1 spectra. The existence of hidden satellites was confirmed by observing the differences between the normalized spectra above and below the L1 edge.

Relativistic calculation of Kα hypersatellite line energies and transition probabilities for selected atoms with 12 ⩽ Z ⩽ 80

The transition probabilities of Kα hypersatellite lines and energy shifts with respect to the corresponding diagram lines are computed using the Dirac–Fock model for several values of atomic number Z throughout the periodic table. The influence of the Breit interaction on the Kα1h/Kα2h line intensity ratio, Kα1h and Kα2h line energy shifts and Kα1h to Kα2h line energy splitting is evaluated. Double-K shell hole threshold values for selected elements with 23 ⩽Z⩽ 30, calculated within the same approach, are compared with available experimental results.

KLL Auger resonant Raman transition in metallic Cu and Ni

High energy resolution KL 23L 23 Auger spectra of polycrystalline Cu and Ni were measured using photon energies up to about 50 eV above the K-absorption edge and down to 5 eV (Cu KLL) and 4 eV (Ni KLL) below threshold. The spectra show strong satellite structures varying considerably as a function of the photon energy. In the sub-threshold region the linear dispersion of the diagram line energy positions and a distortion of the line shape as a function of photon energy, attributable to the Auger resonant Raman process, is clearly observed, indicating the one-step nature of the Auger emission. These changes in the resonant spectra are interpreted using a simple model based on resonant scattering theory in combination with partial density of states obtained from cluster molecular orbital (DV- Xα) calculations.

A study of K x‐ray hyper‐satellites and KMM radiative Auger effect (RAE) of the elements 19 ≤ Z ≤ 25 by photon excitation

AbstractK x‐ray emission spectra were generated by photon excitation to study the Kα hyper‐satellites, KβL1, Kβ5 satellites and KMM RAE structures of the elements 19⩽Z⩽25 using a wavelength dispersive spectrometer with LiF 200 and LiF 220 crystals. The Z‐dependence of the energy shift and relative intensity of these lines with respect to the diagram lines were studied except in the case of KMM RAE constituent peaks, for which only energy shifts were examined. The measured energy shifts and relative intensities are compared with the available theoretical predictions. Three of the constituent peaks in the KMM RAE structure are assigned K‐M1M2 (3P), K‐M1M2 (1P) and K‐M1M1 (1S) transitions. Copyright © 2006 John Wiley & Sons, Ltd.

TargetK-vacancy production by2.5to25MeV∕amuAr, Kr, and Xe ions

Cross sections have been measured for $K\ensuremath{\alpha}$ x-ray production in targets of Al, Ti, Cu, Zr, Ag, Sm, and Ta by Ar, Kr, and Xe ions ranging in energy from $2.5\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}25\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}∕\mathrm{amu}$. In addition, the degree of simultaneous $L$-shell ionization and the enhancement of the $K\ensuremath{\alpha}$ diagram lines due to secondary ionization processes were assessed by performing high-resolution spectral measurements on Al, Ti, V, Co, and Cu targets. This information was used to correct for the $K\ensuremath{\alpha}$ x-ray yield produced by electron bombardment and photoionization, and to calculate the fluorescence yields needed to convert the $K\ensuremath{\alpha}$ x-ray production cross sections into $K$-vacancy production cross sections. The resulting cross sections were compared with the predictions of the perturbed stationary state approximation with corrections for projectile energy loss, Coulomb deflection, and relativistic effects (ECPSSR theory). Also, the scaling properties of the $K\ensuremath{\alpha}$ x-ray production cross sections were examined and a semiempirical (universal) curve was deduced that reproduces the measured cross sections to within $\ifmmode\pm\else\textpm\fi{}30%$ on average.

Evolution of satellite lines accompanying photoionization

Evolution of the Auger and X-ray satellite lines was studied. The experimental data for the intensity ratio of the satellite line relative to the diagram line accompanying photoionization as a function of incident photon energy were fitted to the theoretical models based on the adiabatic approximation. The Thomas model, the Vatai model, the model of Roy et al. and its modification were considered. Comparison of these models was made and the difference between four models was discussed.

Predicting the Phase Behavior of Nitrogen + n-Alkanes for Enhanced Oil Recovery from the SAFT-VR Approach: Examining the Effect of the Quadrupole Moment

The phase behavior of nitrogen + n-alkanes is studied within the framework of the statistical associating fluid theory for potentials of variable range (SAFT-VR). The effect of the quadrupole moment of nitrogen on the phase behavior is considered through an extension of the SAFT-VR equation that includes an additional contribution to the Helmholtz free energy due to quadrupolar interactions. A significant improvement in the description of the phase diagram of the binary mixtures of nitrogen with different n-alkanes is obtained with the new approach when compared to predictions from the original SAFT-VR EOS (i.e., without the quadrupolar term). The experimental value for the quadrupole moment of nitrogen is used in the new equation; thus, no additional parameters are employed. Given the nonideal nature of the binary mixtures, a binary interaction parameter is needed to describe the full-phase diagram and high-pressure critical lines of these systems; however, this can be fitted to a single system and successfully used to predict the phase behavior of other binary mixtures without additional fitting. Furthermore, only a single, transferable, cross-energy parameter is required when the quadrupolar term is considered, whereas a cross-range parameter is also needed with the original SAFT-VR approach. The inclusion of the quadrupolar term in the equation of state therefore reduces the need to use effective parameters by explicitly including at the molecular level interactions due to the quadrupole moment.

Natural widths and Coster–Kronig transitions of L X-ray spectra in elements between Pd and Sb

The Lα and Lβ X-ray emission spectra in the elements between Pd ( Z=46) and Sb ( Z=51) were measured using a high-resolution double-crystal vacuum spectrometer. The relative intensities of satellite structures, which originate in L 1 L 3 M 4,5 Coster–Kronig transitions, were estimated to that of each diagram line, and compared with calculated values. According to the work of Chen et al. [1977a. Theoretical L-shell Coster–Kronig energies 11⩽ Z⩽103. At. Data Nucl. Data Tables 19, 97–151], Salgueiro et al. [1987. J. Phys. (Paris) 48 Colloq. C9, 609] and Vlaicu et al. [1998. Investigation of the 74W L emission spectra and satellites. Phys. Rev. A 58, 3544] L 1 L 3 M 4 Coster–Kronig transition is forbidden for 50⩽ Z⩽77, and L 1 L 3 M 5 Coster–Kronig transition is forbidden for 50⩽ Z⩽73. The results suggest that L 1 L 3 M 4,5 Coster–Kronig transitions may be allowed even for Sn ( Z=50) and Sb ( Z=51).

On satellites hidden by diagram line in heavy elements Ir, Pt, Au

The hidden satellites due to Coster–Kronig transition especially have the characteristic threshold in their appearance. To clarify the hidden satellites, we measured L β 2 , 3 , 15 spectra below and above the L 1 edge on Ir, Pt, Au. The measured spectra were normalized using L β 1 spectra. The hidden satellite were confirmed as the differences of two normalized spectra.

The evolution of inner-shell multielectronic X-ray spectra from threshold to saturation for low- to high-Z atoms

Inter- and intra-shell electronic correlations in an atom are manifested in, and can be studied through, the X-ray emission spectra of multielectronic transitions. We have measured the spectra of K hα 1,2 hypersatellites (HS), Kα 3,4 satellites (S), and the 3d electron shake-up satellites (D) accompanying the Kα 1,2 diagram lines, and their evolution from the double-ionization threshold, for selected 4- and 5-row elements of the periodic table. These spectra originate in the [1 s] −1, [2p] −1, and [3d] −1 spectator two-electron transitions [1 s] −2→[1s2p] −1, [1s2p] −1→[2p] −2, and [1s3d] −1→[2p3d] −1 respectively. Photoexcitation by monochromatized synchrotron radiation together with high-resolution crystal spectrometers were employed. Ab initio relativistic multiconfigurational Dirac–Fock (RMCDF) calculations reproduce the spectra very well for all transitions, with the HS spectra showing a strong dependence on QED effects. The excitation thresholds were determined accurately. The threshold-to-saturation energy range of the intensity was found to depend strongly on the principal quantum number n of the spectator hole. For example, for Cu, ranges of 2%, 10%, and 60% of the threshold energy are found for the D, S and HS spectra, respectively. Only the D spectrum's evolution conforms to the Thomas model, indicating a dominant shake up/off process. The S and HS spectra seem to be dominated by the knockout (“two-step-one”) process near threshold. The S spectra show a two-regime behavior. Near threshold both shape and intensity vary with excitation energy, and above that only intensity changes are observed. The lower-than-expected K hα 1/K hα 2 intensity ratio found for Z=23–30 and 39–46 indicates that the angular momenta coupling scheme at the regime intermediate between the LS coupling at low-Z and the jj coupling at high-Z may not be fully accounted for by the prevailing theory.

Contribution of the [1s3d] shake process to Kα1,2 spectra in 3d elements

The Kα 1,2 emission lines in 3d transition elements were investigated using a high-resolution anti-parallel crystal spectrometer. A double Lorentzian model of the Kα X-ray emission spectra in these elements has been proved to be able to fit the experimental curve of the diffracted intensity like the case on Cu. Their energy positions, full-width at half-maximum (FWHM), and intensity ratio were obtained by Lorentzian fitting method for these diagram lines. Moreover, the contribution of the 3d spectator hole is experimentally and theoretically confirmed in the Zn Kα 1,2 spectra using GRASP2 code for a convenience of the calculation.

Relativistic calculation of Kβ hypersatellite energies and transition probabilities for selected atoms with 13 ⩽ Z ⩽ 80

Energies and transition probabilities of Kβ hypersatellite lines are computed using the Dirac–Fock model for several values of Z throughout the periodic table. The influence of the Breit interaction on the energy shifts from the corresponding diagram lines and on the Kβh1/Kβh3 intensity ratio is evaluated. The widths of the double-K hole levels are calculated for Al and Sc. The results are compared to experiment and to other theoretical calculations.