Exploring Locality in Molecular Dirac-Coulomb-Breit Calculations: A Perspective

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Relativistic Effects

Background:

• The Dirac-Coulomb-Breit (DCB) operator is crucial for accurate molecular calculations involving relativistic effects and spin-physics.
• High computational cost of the DCB operator necessitates the development of efficient approximations.

Purpose of the Study:

• To explore local integral approximations for the DCB operator.
• To understand the locality of the charge-current distribution originating from the small component.
• To develop and evaluate a new atomic Breit approximation.

Main Methods:

• Analysis of the charge-current distribution's behavior.
• Proposal of an atomic Breit approximation based on gold chain studies.
• Benchmark studies on metal complexes to assess accuracy and performance.

Main Results:

• The proposed atomic Breit approximation demonstrates accuracy and efficiency.
• Insights into the contributions of AO basis constituents to the charge-current distribution.
• Validation of the approximation through benchmark studies.

Conclusions:

• The atomic Breit approximation offers a balance between computational efficiency and accuracy for relativistic molecular calculations.
• This work facilitates the development of low-scaling methods in computational chemistry.
• A deeper understanding of the DCB operator's behavior is achieved.