Positron binding to atoms and apolar molecules: A convergence of theory and experiment

Amaral, Paulo H. R.; Mohallem, José R.

doi:10.1103/physreva.86.042708

Cited by 10 publications

(6 citation statements)

References 33 publications

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“…Beyond the academic curiosity, the annihilation process is the basis of the Positron Emission Tomography as a powerful medicinal imaging technique . Accordingly, a large body of experimental, and theoretical and computational, studies have been conducted recently on polyatomic and diatomic, positronic species in order to trace the sticking site of the positron. These studies reveal that in general the positronic density is very diffuse and is not centered between bonds but behind the most electronegative atom of the molecule (the cases with two or more atoms with equal electronegativity are more complicated) .…”

Section: Introductionmentioning

confidence: 99%

On the Nature of the Positronic Bond

Goli

Shahbazian

2019

ChemPhysChem

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Recently it has been proposed that the positron, the anti‐particle analog of the electron, is capable of forming an anti‐matter bond in a composite system consists of two hydride anions and a positron [Angew. Chem. Int. Ed. 57, 8859–8864 (2018)]. In order to dig into the nature of this novel bond the newly developed multi‐component quantum theory of atoms in molecules (MC‐QTAIM) is applied to this positronic system. The topological analysis reveals that this species is composed of two atoms in molecules, each containing a proton and half of the electronic and the positronic populations. Further analysis elucidates that the electron exchange phenomenon is virtually non‐existent between the two atoms and no electronic covalent bond is conceivable in between. On the other hand, it is demonstrated that the positron density enclosed in each atom is capable of stabilizing interactions with the electron density of the neighboring atom. This electrostatic interaction suffices to make the whole system bonded against all dissociation channels. Thus, the positron indeed acts like an anti‐matter glue between the two atoms.

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Section: Introductionmentioning

confidence: 99%

On the Nature of the Positronic Bond

Goli

Shahbazian

2019

ChemPhysChem

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“…Alternatively, phenomenological models have also been constructed using global molecular parameters (e.g. permanent dipole moment, molecular polarizability and the number of π bonds) to predict binding energies [12][13][14][15][16]. Trends in binding energy can be captured for families of molecules using this approach.…”

Section: Introductionmentioning

confidence: 99%

Influence of geometry on positron binding to molecules

Danielson¹,

Ghosh²,

Surko³

2021

J. Phys. B: At. Mol. Opt. Phys.

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Annihilation studies have established that positrons bind to most molecules. They also provide measurements of the positron-molecule binding energies, which are found to vary widely and depend upon molecular size and composition. Trends of binding energy with global parameters such as molecular polarizability and dipole moment have been discussed previously. In this paper, the dependence of binding energy on molecular geometry is investigated by studying resonant positron annihilation on selected pairs of isomers. It is found that molecular geometry can play a significant role in determining the binding energies even for isomers with very similar polarizabilities and dipole moments. The possible origins of this dependence are discussed.

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“…Note that a recent paper [22] combined a hard-sphere repulsive core with the polarization potential to model positron binding to atoms and nonpolar molecules. While the two models bear some similarity, the physics of positron binding to neutral atoms and nonpolar species is very different from that of binding to strongly polar molecules explored in this work.…”

Section: Introductionmentioning

confidence: 99%

Effect of dipole polarizability on positron binding by strongly polar molecules

Gribakin

Swann

2015

J. Phys. B: At. Mol. Opt. Phys.

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Abstract.A model for positron binding to polar molecules is considered by combining the dipole potential outside the molecule with a strongly repulsive core of a given radius. Using existing experimental data on binding energies leads to unphysically small core radii for all of the molecules studied. This suggests that electron-positron correlations neglected in the simple model play a large role in determining the binding energy. We account for these by including the polarization potential via perturbation theory and non-perturbatively. The perturbative model makes reliable predictions of binding energies for a range of polar organic molecules and hydrogen cyanide. The model also agrees with the linear dependence of the binding energies on the polarizability inferred from the experimental data [Danielson et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 235203]. The effective core radii, however, remain unphysically small for most molecules. Treating molecular polarization nonperturbatively leads to physically meaningful core radii for all of the molecules studied and enables even more accurate predictions of binding energies to be made for nearly all of the molecules considered.

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Positron binding to atoms and apolar molecules: A convergence of theory and experiment

Cited by 10 publications

References 33 publications

On the Nature of the Positronic Bond

On the Nature of the Positronic Bond

Influence of geometry on positron binding to molecules

Effect of dipole polarizability on positron binding by strongly polar molecules

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