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Updated: Aug 22, 2025
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Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles
Published on: November 27, 2015
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Mn2 Dimers Encapsulated in Silicon Cages: A Complex Challenge to MC-SCF Theory
Vaibhav Khanna1, John Ewart McGrady1
1Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK.
Molecules (Basel, Switzerland)
|November 11, 2022
Summary
Strong static correlation exists in manganese-silicon clusters, affecting Mn-Si bonds and Mn-Mn interactions. Generalized Active Spaces (GAS) better capture this correlation than Restricted Active Spaces (RAS).
Area of Science:
- Computational Chemistry
- Materials Science
- Quantum Mechanics
Background:
- Endohedral manganese-silicon clusters are investigated for their electronic structure.
- Understanding static correlation is crucial for accurately modeling these systems.
Purpose of the Study:
- To analyze static correlation in Mn2Si10, Mn2Si12, and [Mn2Si13]+ clusters.
- To compare the effectiveness of Generalized Active Spaces (GAS) and Restricted Active Spaces (RAS) in capturing static correlation.
Main Methods:
- Multi-Configuration Self-Consistent Field (MC-SCF) wavefunctions were computed.
- Restricted Active Spaces (RAS) and Generalized Active Spaces (GAS) were employed to constrain trial wavefunctions.
Main Results:
- Strong static correlation was observed in both Mn-Si bonds ('in-out correlation') and between Mn centers ('up-down correlation').
- GAS approaches captured more static correlation than RAS, especially in high-symmetry cases.
- Key correlating pairs remained consistent across different silicon cage sizes.
Conclusions:
- The electronic structure of the embedded Mn2 unit is largely independent of the silicon cage size.
- GAS is a more effective method for describing static correlation in these endohedral clusters.
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