On orthogonality constrained multiple core-hole states and optimized effective potential method

Area of Science:

• Quantum Chemistry
• Computational Physics
• Theoretical Chemistry

Background:

• Accurate calculation of core-hole states is crucial for understanding atomic and molecular electronic structure.
• Existing methods like the Delta self-consistent field (Δ-SCF) approach have limitations in handling multiple core-hole states.
• The optimized effective potential (OEP) methodology offers a promising alternative for electronic structure calculations.

Purpose of the Study:

• To develop a unified computational framework for constructing and calculating multiple core-hole states within the OEP methodology.
• To extend the constrained OEP method for accurate prediction of single and double core ionization energies.
• To investigate the implementation of this method for atoms and molecules.

Main Methods:

• Development of a constrained OEP method incorporating orthogonality constraints for Slater determinants.
• Utilizing a direct mapping formulation to derive a local effective potential from the external potential.
• Incorporating correlation corrections from second-order many-body perturbation theory.
• Solving the one-particle Schrödinger equation with the derived local potential.

Main Results:

• Demonstrated a unified framework capable of treating single, double, and multiple core-hole states.
• Calculated single and double core ionization potentials showing agreement with experimental and other computational data.
• The direct mapping formulation ensures the effective potential possesses the symmetry of the external potential.

Conclusions:

• The developed constrained OEP method provides an accurate and unified approach for calculating core-hole states.
• This methodology is readily applicable to both atoms and molecules.
• The study highlights the advantages of the direct mapping formulation for effective potential construction in electronic structure calculations.