Exact Two-Component Relativistic Polarizable Density Embedding.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Relativistic Quantum Mechanics

Background:

• Accurate modeling of solvated systems with relativistic effects is crucial.
• Traditional polarizable embedding models struggle with electron leakage in such systems.
• The eXact 2-Component (X2C) Hamiltonian is a key tool for relativistic calculations.

Purpose of the Study:

• To implement the fragment-based polarizable density embedding (PDE) model within a relativistic framework.
• To address the electron-leakage problem in modeling solvated systems with significant relativistic effects.
• To validate the new relativistic PDE model's accuracy.

Main Methods:

• Integration of the fragment-based PDE model with the X2C relativistic Hamiltonian.
• Comparative calculations of K- and L2,3-edge spectra for water-solvated cysteine.
• Inclusion of counterions (e.g., Na+) to test model robustness.

Main Results:

• The relativistic PDE model successfully eliminates spurious peaks caused by electron leakage.
• Accurate modeling of solvated cysteine spectra, even in the presence of counterions.
• Demonstrated superior performance compared to older polarizable embedding models.

Conclusions:

• The newly implemented relativistic PDE model is a robust and accurate tool for studying solvated systems with relativistic effects.
• This advancement resolves critical issues like electron leakage in complex chemical environments.
• The model provides a reliable approach for spectroscopic predictions in relativistic regimes.