Abstract

The $K\ensuremath{\alpha}$ and $K\ensuremath{\beta}$ x-ray spectra of Se, Y, and Zr were studied experimentally and theoretically in order to obtain information on the $K{\ensuremath{\alpha}}_{1}$ line asymmetry and the spin doublet in $K{\ensuremath{\beta}}_{1,3}$ diagram lines. Using a high-resolution antiparallel double-crystal x-ray spectrometer, we obtained the line shapes, that is, asymmetry index and natural linewidths. We found that the corrected full width at half maximum of the $K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\alpha}}_{2}$ lines as a function of $Z$ is in good agreement with the data in the literature. Furthermore, satellite lines arising from shake-off appear in the low-energy side of the $K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\alpha}}_{2}$ lines in Se but, in Y and Zr, it was very difficult to identify the contribution of the shake process to the overall lines. The $K{\ensuremath{\beta}}_{1,3}$ natural linewidth of these elements was also corrected using the appropriate instrumental function for this type of x-ray spectrometer, and the spin doublet energies were obtained from the peak positions. The corrected full width at half maximum (FWHM) of the $K{\ensuremath{\beta}}_{1}$ x-ray lines increases linearly with $Z$, but this tendency was found to be, in general, not linear for $K{\ensuremath{\beta}}_{3}$ x-ray lines. This behavior may be due to the existence of satellite lines originated from shake processes. Simulated line profiles, obtained using the multiconfiguration Dirac-Fock formalism, accounting for radiative and radiationless transitions and shake-off processes, show a very good agreement with the high-resolution experimental spectra.

Highlights

  • The Kα and Kβ x-ray emission spectra of the 3d transition metals exhibit several peculiar asymmetric line profiles not observed in other elements [1], whose origin has been under investigation and debate [2,3,4,5,6]

  • In order to elucidate the influence of the shake processes on the spectral profile, we investigated in this paper the contribution of [1s3d] shake-off to the asymmetry of Se, Y, and Zr Kα1,2 emission lines, from both experiment and theory, and the natural width of each line in the Kβ1,3 emission spectra of the same elements to obtain the energy values of the spin doublet in detail, using a high-resolution double-crystal x-ray spectrometer

  • After Deutsch et al [4] demonstrated that the line profiles of Cu Kα and Kβ emission lines can be fully accounted for by contributions to the diagram lines from 3d-spectator transitions only, Hölzer et al [6] concentrated on the investigation of Kα and Kβ diagram lines based on the results of Deutsch et al [4] in order to elucidate the origin of the asymmetry using a high-resolution x-ray crystal spectrometer

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Summary

Introduction

The Kα and Kβ x-ray emission spectra of the 3d transition metals exhibit several peculiar asymmetric line profiles not observed in other elements [1], whose origin has been under investigation and debate [2,3,4,5,6]. [18], Chantler et al [19], and Ito et al [20] suggested that the line shapes in Kα1,2 x-ray spectra could be accounted for by the diagram transition and 3s, 3p, and 3d spectator-hole transitions. Ito et al [20] measured systematically the Kα1,2 spectra in the elements from Ca to Ge using an antiparallel two-crystal x-ray spectrometer and elucidated the origin of the asymmetry in the Kα1 emission profile, confirming that the broadening of the linewidths of Kα2 spectra originates from L2-L3M4,5 Coster-Kronig transitions. Combined ab initio Dirac-Fock calculations and high-resolution x-ray emission measurements of Kα1,2 spectra for elements Ca, Ti, and Ge show that the asymmetric line shapes of these emission lines

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