Amazing stuff! Positron bonded molecules!
"... The idea that a chemical bond could be mediated by positrons has been proposed before for the case of two hydride anions, where one or two positrons stabilise nuclei that would normally repel each other. Despite this, the nature of the positronic bond and the extent that it resembles conventional electronic bonds is unclear. ...
In 2019 they reported that positronic covalent bonds between halide anions would be energetically stable. Now they have explored the stability of 2e+[H33−], a molecule that could hypothetically exist where three hydride anions are bonded by two positrons. ..."
In 2019 they reported that positronic covalent bonds between halide anions would be energetically stable. Now they have explored the stability of 2e+[H33−], a molecule that could hypothetically exist where three hydride anions are bonded by two positrons. ..."
From the abstract:
"Computational studies have shown that one or more positrons can stabilize two repelling atomic anions through the formation of two-center positronic bonds. In the present work, we study the energetic stability of a system containing two positrons and three hydride anions, namely 2e+[H33−]. To this aim, we performed a preliminary scan of the potential energy surface of the system with both electrons and positrons in a spin singlet state, with a multi-component MP2 method, that was further refined with variational and diffusion Monte Carlo calculations, and confirmed an equilibrium geometry with D3h symmetry. The local stability of 2e+[H33−] is demonstrated by analyzing the vertical detachment and adiabatic energy dissociation channels. Bonding properties of the positronic compound, such as the equilibrium interatomic distances, force constants, dissociation energies, and bonding densities are compared with those of the purely electronic H3+ and Li3+ systems. Through this analysis, we find compelling similarities between the 2e+[H33−] compound and the trilithium cation. Our results strongly point out the formation of a non-electronic three-center two-positron bond, analogous to the well-known three-center two-electron counterparts, which is fundamentally distinct from the two-center two-positron bond [D. Bressanini, J. Chem. Phys., 2021, 155, 054306], thus extending the concept of positron bonded molecules."
The three-center two-positron bond
Electronic density of H3+ (a), electronic bonding density of Li3+ (b), and positronic bonding density of 2e+[H33−] (c)
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