2025/02/14 by S. K. Gregg, Gregg, S. K., J. Hofierka +5
Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #Chemical Physics (physics.chem-ph) #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Muon and positron interactions and applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2502.10327
openalex publication_date 2025/02/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Positron binding in parabenzoquinone is studied using ab initio many-body theory. The effects of electron-positron correlations including polarization, virtual positronium formation and positron-hole repulsion, as well as those of π bonds, aromaticity, and lone electron pairs, are considered. The binding energy is calculated as 60±16 meV, considerably larger than the 0.0925 meV value inferred from recent scattering calculations of [G. Moreira and M. Bettega, Eur.~Phys.~J.~D \bf 78 (2024)], but substantially smaller than we find in benzene (148±26 meV). The positron contact density (lifetime) is calculated as 8.0×10-3 a.u. (2.48 ns), vs.~1.61× 10-2 a.u. (0.81 ns) in benzene. The decrease (increase) in binding (annihilation rate) in parabenzoquinone compared to benzene is ascribed to the loss of aromaticity: the electron density on the positive oxygen nuclei being relatively harder for the positron to probe compared to the aromatic rings in benzene.