Two-component relativistic density functional method for computing nonsingular complex linear response of molecules...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Relativistic effects and spin-orbit coupling are crucial for accurate electronic structure calculations of heavy elements.
• Linear response theory is essential for understanding molecular properties like polarizability and spectral responses.
• Existing methods may not fully capture the complexity of relativistic effects in molecular response properties.

Purpose of the Study:

• To implement a frequency-dependent two-component relativistic density functional theory (DFT) method using the zeroth order regular approximation (ZORA).
• To enable accurate computations of complex linear response properties, including spin-orbit coupling effects.
• To validate the new method through diverse molecular systems and spectral simulations.

Main Methods:

• Development of a two-component relativistic DFT method based on ZORA.
• Utilized Slater-type atomic orbital basis functions and density fitting techniques.
• Employed damping in computations to obtain complex response and simulated spectra.

Main Results:

• Successfully implemented and validated the frequency-dependent two-component ZORA method.
• Calculated static and dynamic polarizabilities for group 12 atoms, heavy-atom diatomics, gold clusters, and group 8 oxides/metallocenes.
• Demonstrated the ability to simulate spectra by comparing extinction coefficients derived from imaginary polarizability with excitation energy-based spectra.

Conclusions:

• The new relativistic DFT-ZORA method accurately computes complex linear response properties, including spin-orbit coupling.
• The method provides a reliable tool for studying electronic structures and spectral properties of molecules with heavy atoms.
• This work advances theoretical chemistry for predicting molecular behavior in relativistic regimes.