Single-electron fluorine bonding. II. Benchmarking Minnesota density functional approximations and popular ab initio methods for binding energies (BEs) and F-bond distances
Abstract
Companion paper I (Khanal and Arunan, in this issue; arXiv:2610.16629 [physics.chem-ph]) reported reference BEs and F-bond distances for two new databases SEFB-15 (DF⋯CH3) and CSFB-14 (DF⋯NH3). Here, we assess performance of popular ab initio methods (MP2, MP3, MP4(DQ), MP4(SDQ), CCSD, and QCISD) with valence- and full-electron correlation treatments, and sixteen Minnesota DFAs, including M06-2X already assessed in companion paper I. CCSD/AVDZ reproduces reference F-bond distances closely, although BEs predicted by it deviate more. Among the 16 Minnesota DFAs, M08-HX reliably reproduces both reference values for DF⋯CH3 and DF⋯NH3, comparable to M05-2X and M06-2X for DF⋯NH3. Selected meta-GGAs (M06-L, M11-L, and MN15-L) exhibit spurious fractional charge transfer in cationic complexes even at infinite separation, whereas hybrid Minnesota DFAs do not, except M05 and M06 for NH3F+⋯CH3 and NH2F2+⋯CH3. Although M08-HX shows slightly larger monomer delocalization error than M05-2X and M06-2X, it is more reliable for predicting BEs of SEFB complexes, indicating that monomer delocalization error alone does not govern DFA performance. Bader's intermolecular delocalization indices (DIs) further support M08-HX as more reliable than M05-2X and M06-2X for SEFB, while the larger DIs from M05-2X and M06-2X explain the degraded performance of their dispersion-corrected variants for DF⋯CH3, with only a minor impact for DF⋯NH3, highlighting the system-dependent nature of functional delocalization error. Present work reveals that M08-HX is more reliable than M05-2X and M06-2X for open-shell DF⋯CH3 complexes, while all three functionals show comparable reliability for closed-shell DF⋯NH3 complexes.
Related
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BibTeX
@misc{khanal2026singleelectron,
title = {{Single-electron fluorine bonding. II. Benchmarking Minnesota density functional approximations and popular ab initio methods for binding energies (BEs) and F-bond distances}},
author = {Govinda Prasad Khanal and Elangannan Arunan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.23472},
eprint = {2610.23472},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.23472},
}
RIS
TY - UNPB
TI - Single-electron fluorine bonding. II. Benchmarking Minnesota density functional approximations and popular ab initio methods for binding energies (BEs) and F-bond distances
AU - Govinda Prasad Khanal
AU - Elangannan Arunan
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.23472
UR - https://arxiv.org/abs/2610.23472
AB - Companion paper I (Khanal and Arunan, in this issue; arXiv:2610.16629 [physics.chem-ph]) reported reference BEs and F-bond distances for two new databases SEFB-15 (DF⋯CH_3) and CSFB-14 (DF⋯NH_3). Here, we assess performance of popular ab initio methods (MP2, MP3, MP4(DQ), MP4(SDQ), CCSD, and QCISD) with valence- and full-electron correlation treatments, and sixteen Minnesota DFAs, including M06-2X already assessed in companion paper I. CCSD/AVDZ reproduces reference F-bond distances closely, although BEs predicted by it deviate more. Among the 16 Minnesota DFAs, M08-HX reliably reproduces both reference values for DF⋯CH_3 and DF⋯NH_3, comparable to M05-2X and M06-2X for DF⋯NH_3. Selected meta-GGAs (M06-L, M11-L, and MN15-L) exhibit spurious fractional charge transfer in cationic complexes even at infinite separation, whereas hybrid Minnesota DFAs do not, except M05 and M06 for NH_3F^+⋯CH_3 and NH_2F_2^+⋯CH_3. Although M08-HX shows slightly larger monomer delocalization error than M05-2X and M06-2X, it is more reliable for predicting BEs of SEFB complexes, indicating that monomer delocalization error alone does not govern DFA performance. Bader's intermolecular delocalization indices (DIs) further support M08-HX as more reliable than M05-2X and M06-2X for SEFB, while the larger DIs from M05-2X and M06-2X explain the degraded performance of their dispersion-corrected variants for DF⋯CH_3, with only a minor impact for DF⋯NH_3, highlighting the system-dependent nature of functional delocalization error. Present work reveals that M08-HX is more reliable than M05-2X and M06-2X for open-shell DF⋯CH_3 complexes, while all three functionals show comparable reliability for closed-shell DF⋯NH_3 complexes.
ER -