Atomic inner-shell level energies determined by absorption spectrometry with synchrotron radiation

Absolute energies of the $\mathrm{Ar}K$, $\mathrm{Kr}K$, and $\mathrm{Xe}{L}_1$, $L_2$, and $L_3$ levels have been determined from absorption edges measured with synchrotron radiation. The double-crystal x-ray monochromator was calibrated by a method that ties the energy scale directly to the crystal lattice constant and $\mathrm{hc}$. Theoretical model spectra were constructed from ≥ 4 Lorentzians representing the lowest-energy one-electron electric-dipole transitions to bound excited states, and an arc tangent representing transitions to higher bound states and to the continuum. The transition energies were found by minimizing ${\chi }^2$ for the fit of the theoretical spectrum shape to the data. Energy differences from optical spectral series were used to relate the excited-state energies to the vacuum level. Results are compared with earlier measurements and with theory.