Journal of Chemical Theory and Computation· 2026Q1
Spin Manifolds in the [Fe4S4(SCH3)4]2– Cluster from Localized Active Space State Interaction Singles and Pair-Density Functional Theory
- 1citations
- Q1SCImago
- 2026year
Short summary
Localized Active Space State Interaction Singles (LASSIS) combined with pair-density functional theory (PDFT) successfully describes the dense manifold of low-lying electronic states in the [Fe4S4(SCH3)4]2– cluster, revealing distinct spin-state energy manifolds.
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Key points
- Developed LASSIS combined with PDFT to model the [Fe4S4(SCH3)4]2– cluster's electronic structure.
- The method treats all low-lying states within a common model-space Hamiltonian, yielding a single set of orthogonal states.
- Results show distinct manifolds of spin-state energies for the cluster.
- The observed pattern of spin-state manifolds is consistent across different active space sizes (22e/20o to 54e/36o).
- Implemented GPU acceleration for computationally intensive LASSIS workflow components.
AI-generated from the title and abstract; the full text is not read.
Abstract
Abstract Iron–sulfur clusters play central roles in biological photosynthesis, respiration, and catalysis. The [Fe4S4(SCH3)4]2– cluster possesses a dense manifold of low-lying electronic states arising from strong magnetic interactions among the Fe centers, making its electronic structure challenging to describe theoretically. Previous multireference studies have generally optimized excited states individually while neglecting the interactions among low-lying states. In this work, we investigate the low-lying electronic states of [Fe4S4(SCH3)4]2– using localized active space state interaction singles (LASSIS) combined with pair-density functional theory (PDFT). By treating all states within a common model-space Hamiltonian, LASSIS generates a single set of orthogonal low-lying states. The resulting spin-state energies organize into distinct manifolds. The same overall pattern is obtained for active spaces ranging from 22 electrons in 20 orbitals to 54 electrons in 36 orbitals. To enable these calculations, we also implement GPU acceleration for the most computationally demanding components of the LASSIS workflow.
The authors' abstract, as published at the source. Journal of Chemical Theory and Computation, 2026 · DOI ↗
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Field: Atomic and Molecular Physics, and Optics
Atomic and Molecular Physics, and OpticsPhysics and Astronomy