Fock-space multireference coupled cluster calculations of Auger energies of noble gas elements using relativistic spinors.

We report the Auger and Coster-Kronig transition energies (related to double ionization potentials) of noble gas elements obtained using the Fock-space multireference coupled cluster (FSMRCC) method with relativistic spinors. The resulting Auger and Coster-Kronig lines are found to be in agreement with the experimental data and with other reference theoretical estimates. To the best of our knowledge, no prior report of relativistic calculations is available for Auger transition energies at the FSMRCC level of theory. The ionization potentials resulted from this method with no extra cost are also found to be in agreement with experiment, particularly the outer-valence ones. Interestingly, the FSMRCC and the multiconfiguration Dirac-Fock calculations exhibit an inversion in the ³ P energy levels of the xenon atom for N _4,5 -O ₂₃ O ₂₃ Auger transitions, where the ³ P _j state energies appear in the order J = 1, 0, 2, a feature which can be verified experimentally.