Relativistic calculations of X-ray photoelectron spectra and the accuracy of the IOTC method.

In this paper, the authors have applied the infinite-order two-component (IOTC) method to study the X-ray spectra of noble gases. The effect of spin–orbit coupling is introduced via the restricted active space interaction (RASSI) method with the use of the atomic mean-field AMFI integrals. For the deep core energies the discrepancies between the experimental and calculated values can be still quite large. To explain these differences the quantum electrodynamic corrections have been calculated such as Breit energy, self-energy and vacuum polarisation. The comparison between results of the IOTC method and the Douglas–Kroll–Hess (DKHn) approximation has been presented as well. [ABSTRACT FROM AUTHOR]