The Jahn-Teller effect: a case of incomplete theory for d4 complexes?
Jorge David1, Doris Guerra, Albeiro Restrepo
1Escuela de Ciencias y Humanidades, Departamento de Ciencias básicas, Universidad Eafit AA 3300, Medellín, Colombia.
Relativistic effects significantly alter molecular structures for group 9 monoanionic hexafluorides (MF(6)(-)). Calculations show spin-orbit coupling favors octahedral symmetry, contrary to nonrelativistic predictions.
Area of Science:
- Computational chemistry
- Inorganic chemistry
- Quantum chemistry
Background:
- Group 9 elements (Co, Rh, Ir) form monoanionic hexafluorides (MF(6)(-)).
- Understanding molecular geometry is crucial in inorganic chemistry.
- Relativistic effects can significantly impact electronic structure and properties.
Purpose of the Study:
- To investigate the role of relativistic effects on the geometries of MF(6)(-) (M = Co, Rh, Ir).
- To compare relativistic and nonrelativistic predictions for molecular symmetries.
- To determine the ground state symmetries of these hexafluorides.
Main Methods:
- Four-component Dirac-DFT calculations for geometry optimization.
- Relativistic coupled-cluster singles and doubles with perturbative triples (CCSD(T)) for energy calculations.
- Analysis of spin-orbit coupling effects on molecular structure.
Main Results:
- Relativistic calculations predict octahedral (O(h)) ground state symmetries for all studied MF(6)(-).
- Nonrelativistic calculations suggest a deviation towards D(4h) symmetries.
- Spin-orbit coupling is identified as a key factor influencing geometrical preferences.
Conclusions:
- Relativistic effects play a critical role in determining the molecular structure of group 9 monoanionic hexafluorides.
- The inclusion of spin-orbit coupling is essential for accurately predicting the ground state symmetries.
- These findings highlight the importance of relativistic quantum chemistry in understanding inorganic compounds.
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