Properties of closed-shell superheavy element hydrides and halides using coupled-cluster method and density...

Area of Science:

• Computational chemistry
• Relativistic quantum mechanics
• Superheavy element chemistry

Background:

• Superheavy elements present unique chemical challenges due to relativistic effects.
• Accurate theoretical predictions are crucial for understanding their properties.

Purpose of the Study:

• To calculate bond lengths, force constants, and dissociation energies for superheavy element monohydrides and halides.
• To investigate the impact of spin-orbit coupling (SOC) on these molecular properties.
• To evaluate the performance of different computational methods, including coupled-cluster (CC) and density functional theory (DFT).

Main Methods:

• Coupled-cluster singles and doubles with perturbative triples (CCSD(T)) calculations.
• Relativistic effective core potentials were employed.
• Spin-orbit coupling (SOC) was included in both self-consistent field (SCF) and post-SCF calculations.
• Density functional theory (DFT) with various exchange-correlation (XC) functionals (PBE0, B97-3) was used for comparison.

Main Results:

• CCSD(T) calculations with SOC provide accurate estimates for superheavy element molecule properties.
• SOC significantly influences molecular trends.
• SOC-CCSD results align well with KR-CCSD, but SOC-CCSD(T) shows larger errors for elements like 114.
• PBE0 performs best in scalar-relativistic DFT calculations, while B97-3 is superior when SOC is considered.

Conclusions:

• Spin-orbit coupling is essential for accurate theoretical studies of superheavy element molecules.
• The choice of computational method and functional is critical for reliable predictions.
• B97-3 shows promise as an accurate XC functional for SOC-inclusive DFT calculations in this domain.