The Electronic Structure of Planar Rhombic Co₂O₂.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• The electronic structure of low-lying valence states in Co2O2 is not fully understood.
• Accurate theoretical prediction of the ground state requires advanced computational methods.

Purpose of the Study:

• To computationally investigate the low-lying valence states of the planar rhombic Co2O2 structure.
• To determine the ground state electronic configuration using various quantum chemical methods.

Main Methods:

• Density Functional Theory (DFT)
• Coupled-Cluster Singles and Doubles with Perturbative Triples (CCSD(T))
• Complete Active Space Self-Consistent Field (CASSCF)
• Complete Active Space Perturbation Theory to Second Order (CASPT2)

Main Results:

• DFT, CCSD(T), and CASSCF methods suggest a high-spin septet ground state.
• CASPT2 calculations indicate a singlet ground state (1Ag).
• The singlet state exhibits a strong diatropic ring current, with contributions from sigma and pi orbitals.

Conclusions:

• The ground state of Co2O2 is sensitive to the chosen computational method.
• Both static and dynamic electron correlation are crucial for accurate ground state determination.
• The singlet state displays significant magnetically induced current density (MICD) properties.