Relativistic all-electron two-component self-consistent density functional calculations including one-electron scalar...

Area of Science:

• Theoretical Chemistry
• Computational Quantum Chemistry
• Relativistic Quantum Chemistry

Background:

• Accurate prediction of molecular properties is crucial in chemistry.
• Relativistic effects, particularly spin-orbit coupling, significantly influence properties of heavier elements.
• Existing computational methods may not fully capture these effects.

Purpose of the Study:

• To implement a robust computational method for calculating molecular properties.
• To incorporate two-electron spin-orbit effects within a relativistic framework.
• To evaluate the performance of different density functionals for these calculations.

Main Methods:

• Gaussian basis-set two-component self-consistent field (SCF) method.
• Fourth-order Douglas-Kroll-Hess (DKH) approximation for relativistic effects.
• Boettger's screened-nuclear spin-orbit approximation for two-electron effects.
• Generalized Kohn-Sham scheme for variational treatment of spin-orbit interaction.
• Noncollinear spin-density approximation for open-shell systems.

Main Results:

• Calculated equilibrium bond lengths, harmonic vibrational frequencies, and bond dissociation energies.
• Demonstrated the method's applicability with local spin-density (LSD), generalized gradient approximation (GGA), and hybrid functionals.
• Provided benchmark results for a set of molecules.

Conclusions:

• The implemented method provides accurate predictions of molecular properties, including those influenced by spin-orbit coupling.
• The approach is versatile, allowing for the use of various density functionals.
• This work advances relativistic quantum chemistry calculations.