Relativistic Corrections to the Exchange-Correlation Energy Functional
During recent years the development of fully relativistic methods for electronic structure calculations has been a major trend both in atomic physics and computational quantum chemistry (see e.g.[1–5]). Looking at Gold as the prime candidate for relativistic effects this trend is easy to understand: When going from a nonrelativistic to a relativistic treatment the ionization potential of Au increases by 30% , the bond length of AuH is contracted by 13% and its dissociation energy increases by about 50% . The differences are even more dramatic for the electron affinity: For Au a nonrelativistic CI-calculation  gives a value of 1.02 eV compared with 2.28 eV obtained with a fully relativistic Coupled-Cluster calculation . Moreover, the fact that the relativistic Hartree-Fock (RHF) approach leads to 7.48 eV  for the electron affinity of Au while the nonrelativistic HF value is 0.10 eV, clearly demonstrates that relativistic and exchange-correlation (xc) effects are nonadditive.
KeywordsGround State Energy Correlation Energy Relativistic Correction Transverse Part Photon Propagator
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