ZORA Gaussian basis sets for Fr, Ra, and Ac

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Relativistic Effects

Background:

• Accurate theoretical calculations require robust basis sets.
• Relativistic effects are crucial for heavy elements like Fr, Ra, and Ac.
• Existing basis sets may not adequately describe these heavy elements under relativistic approximations.

Purpose of the Study:

• To develop and present new segmented all-electron basis sets for Fr, Ra, and Ac.
• To adapt these basis sets for use with the zeroth-order regular approximation (ZORA).
• To evaluate the performance of these new basis sets in relativistic calculations.

Main Methods:

• Construction of double and triple zeta valence qualities plus polarization functions (DZP and TZP) basis sets.
• Reoptimization of contraction coefficients and augmentation with diffuse functions (ADZP-ZORA, ATZP-ZORA).
• Application of ZORA-B3LYP level of theory for property calculations.

Main Results:

• Calculated ionization energies for Fr, Ra, and Ac.
• Determined bond lengths, dissociation energies, vibrational frequencies, and dipole polarizabilities for diatomics.
• Validated the accuracy of the new basis sets against benchmark theoretical and experimental data.

Conclusions:

• The developed ADZP-ZORA and ATZP-ZORA basis sets provide reliable and accurate results for relativistic calculations.
• These basis sets are suitable for studying the electronic properties of Fr, Ra, and Ac.
• The performance of ZORA was evaluated against second-order Douglas-Kroll-Hess Hamiltonians.