文章基本信息

标题：New Insight into the Ground State of FePc: A Diffusion Monte Carlo Study
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作者：Tom Ichibha ; Zhufeng Hou ; Kenta Hongo 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2017
卷号：7
期号：1
DOI：10.1038/s41598-017-01668-6
语种：English
出版社：Springer Nature
摘要：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.