Interaction-Strength Interpolation Method for Main-Group Chemistry: Benchmarking, Limitations, and Perspectives.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• The interaction-strength-interpolation (ISI) functional is designed by interpolating between weak and strong coupling limits.
• It incorporates exact-exchange and Görling-Levy second-order energy for improved accuracy.

Purpose of the Study:

• To evaluate the performance of the original ISI exchange-correlation functional for main group chemistry.
• To analyze the functional's dependence on basis sets, ground-state orbitals, and size-consistency.
• To identify both expected limitations and unexpected strengths of the ISI functional.

Main Methods:

• Testing the ISI functional on main group chemical systems.
• Detailed analysis of basis-set dependence.
• Investigation of ground-state orbital dependency and size-consistency effects.

Main Results:

• The ISI functional exhibits expected limitations for atomization energies.
• Unexpectedly good performance was observed for the interaction energy of dispersion-bonded complexes.
• The ISI correlation, when applied as a correction to Hartree-Fock, demonstrated strong results for these complexes.

Conclusions:

• The ISI functional has specific limitations, particularly for atomization energies in main group chemistry.
• Its application as a correction to Hartree-Fock shows promise for accurately describing dispersion-bonded interactions.
• Further research into refining the ISI functional for broader chemical applications is warranted.