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New Insight into the Ground State of FePc: A Diffusion Monte Carlo Study

We have applied DMC to evaluate relative stability of the possible electronic configurations of an isolated FePc under D (4h) symmetry, considering some fixed nodes generated from different methods. They predict A (2g) ground state consistently, supporting preceding DFT studies, with confidence over...

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Detalles Bibliográficos
Autores principales: Ichibha, Tom, Hou, Zhufeng, Hongo, Kenta, Maezono, Ryo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435675/
https://www.ncbi.nlm.nih.gov/pubmed/28515425
http://dx.doi.org/10.1038/s41598-017-01668-6
Descripción
Sumario:We have applied DMC to evaluate relative stability of the possible electronic configurations of an isolated FePc under D (4h) symmetry, considering some fixed nodes generated from different methods. They predict A (2g) ground state consistently, supporting preceding DFT studies, with confidence overcoming the ambiguity about exchange-correlation (XC) functionals. By comparing DMC with several XC, we clarified the importance of the short-range exchange to describe the relative stability. We examined why the predicted A (2g) is excluded from possible ground states in the recent ligand field based model. Simplified assumptions made in the superposition model are identified to give unreasonably less energy gain for A (2g) when compared with the reality. The state is found to have possible reasons for the stabilization, reducing the occupations from an unstable anti-bonding orbital, avoiding double occupation of a spatially localized orbital, and gaining exchange energy by putting a triplet spin pair in degenerate orbitals.