Implementation of the diagonalization-free algorithm in the self-consistent field procedure within the four-component...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Relativistic Quantum Chemistry

Background:

• The self-consistent field (SCF) method is crucial for electronic structure calculations.
• Traditional SCF methods often rely on computationally expensive diagonalization steps.
• Adapting efficient methods to relativistic quantum chemistry is essential for heavy elements.

Purpose of the Study:

• To implement and analyze a diagonalization-free SCF approach within a four-component relativistic framework.
• To refine the algorithm for improved stability and efficiency, especially for challenging initial guess scenarios.
• To demonstrate the performance of the enhanced method on complex heavy-metal systems.

Main Methods:

• Adaptation of a Thouless-expansion-based diagonalization-free SCF method.
• Implementation within the ReSpect program package for four-component relativistic calculations.
• Analysis of the method's performance on systems with difficult initial guesses.

Main Results:

• Successful implementation of the diagonalization-free SCF method in the four-component relativistic scheme.
• Proposed modifications enhance the algorithm's stability and efficiency.
• Calculations on heavy-metal complexes show the method is approximately twice as fast as traditional diagonalization.

Conclusions:

• The adapted diagonalization-free SCF method provides a robust and efficient alternative for relativistic electronic structure calculations.
• This advancement is particularly beneficial for large, complex heavy-metal systems.
• The improved method accelerates computational chemistry simulations.