Segmented Contracted Douglas-Kroll-Hess Adapted Basis Sets for Lanthanides.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Relativistic Quantum Chemistry

Background:

• Accurate electronic structure calculations are crucial for understanding chemical properties.
• Lanthanides present unique challenges due to their electronic structure and relativistic effects.
• Development of efficient and accurate basis sets is essential for computational studies.

Purpose of the Study:

• To present novel segmented contracted scalar-relativistic all-electron basis sets for lanthanides (La-Lu).
• To evaluate the performance of these basis sets in atomic and molecular calculations.
• To provide a reliable computational tool for relativistic density functional theory (DFT) studies.

Main Methods:

• Development of segmented contracted scalar-relativistic basis sets of (23s16p12d6f)/[18s12p9d3f] size.
• Atomic test calculations using scalar-relativistic Hartree-Fock (HF) level.
• Molecular test calculations for lanthanide trihalides (LnX3) using PBE0 hybrid DFT.

Main Results:

• Basis sets accurately describe ionization potentials (IP1-IP4) and d-f, d-p excitation energies.
• Mean absolute errors achieved are 0.003 eV (IP1) to 0.098 eV (IP4).
• Molecular calculations show lower total energies and comparable accuracy to existing basis sets.

Conclusions:

• The proposed basis sets offer a significant improvement in accuracy for atomic properties compared to similar-sized sets.
• They provide reliable results for lanthanide trihalides in DFT calculations.
• These basis sets are valuable for advanced relativistic quantum chemical studies of lanthanides.