Quantum electrodynamic corrections for molecules: Vacuum polarization and electron self-energy in a two-component...

Area of Science:

• Atomic and Molecular Physics
• Quantum Electrodynamics (QED)
• Computational Chemistry

Background:

• Quantum electrodynamic (QED) effects are crucial for accurate predictions of atomic and molecular properties.
• Previous calculations often relied on computationally expensive four-component methods.
• The zeroth order regular approximation (ZORA) offers a quasi-relativistic alternative.

Purpose of the Study:

• To implement and evaluate vacuum polarization (VP) and electron self-energy (SE) as QED corrections within a two-component ZORA framework.
• To assess the efficiency and accuracy of this approach compared to established methods.
• To calculate QED contributions for a range of atomic and molecular systems.

Main Methods:

• Implementation of VP using the Uehling potential.
• Incorporation of SE using effective potentials (Flambaum and Ginges, Pyykkö and Zhao).
• Application of a two-component ZORA framework for relativistic calculations.
• Comparison of perturbative and self-consistent treatments for gold's Kohn-Sham orbital energies.

Main Results:

• QED corrections were successfully calculated for ionization energies, valence orbital energies, and transition energies in various atomic and molecular systems.
• The two-component ZORA approach demonstrated efficiency in obtaining QED corrections.
• Results showed excellent agreement with corresponding four-component relativistic calculations.

Conclusions:

• The two-component ZORA framework provides an efficient and accurate method for incorporating QED corrections.
• This approach is suitable for a wide range of atomic and molecular calculations.
• The study validates the use of ZORA for precise QED predictions in relativistic systems.