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Mitroy, Jim; Zhang, Jun‐Yi

doi:10.1103/physreva.83.064701

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…(11) can be evaluated with the RS expansion for the APMO wavefunction, 63,64 (20) where the subscripts indicate the perturbation order andT the excitation operators. 60 Denoting the inner product evaluated up to order n as…”

Section: Self-energy Approximationsmentioning

confidence: 99%

“…Explicitly correlated Gaussian (ECG) methodologies, [4][5][6][7][8] quantum Monte Carlo (QMC), [9][10][11] and full configuration interaction (FCI) 12,13 methods have demonstrated superior performance in the description of e-p correlation and the estimation of positron binding energies, PBEs. Despite their proven accuracy, these approaches are extremely computationally demanding and calculations are only feasible for relatively small systems, namely, atoms, [14][15][16][17][18][19] diatomic molecules, 18,[20][21][22][23] and linear triatomics. 14,24 A notable exception is the positron-formaldehyde study by Strasburger.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of positron binding energies using the generalized any particle propagator theory

Romero

Charry

Flores‐Moreno

et al. 2014

The Journal of Chemical Physics

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We recently extended the electron propagator theory to any type of quantum species based in the framework of the Any-Particle Molecular Orbital (APMO) approach [J. Romero, E. Posada, R. Flores-Moreno, and A. Reyes, J. Chem. Phys. 137, 074105 (2012)]. The generalized any particle molecular orbital propagator theory (APMO/PT) was implemented in its quasiparticle second order version in the LOWDIN code and was applied to calculate nuclear quantum effects in electron binding energies and proton binding energies in molecular systems [M. Díaz-Tinoco, J. Romero, J. V. Ortiz, A. Reyes, and R. Flores-Moreno, J. Chem. Phys. 138, 194108 (2013)]. In this work, we present the derivation of third order quasiparticle APMO/PT methods and we apply them to calculate positron binding energies (PBEs) of atoms and molecules. We calculated the PBEs of anions and some diatomic molecules using the second order, third order, and renormalized third order quasiparticle APMO/PT approaches and compared our results with those previously calculated employing configuration interaction (CI), explicitly correlated and quantum Montecarlo methodologies. We found that renormalized APMO/PT methods can achieve accuracies of ~0.35 eV for anionic systems, compared to Full-CI results, and provide a quantitative description of positron binding to anionic and highly polar species. Third order APMO/PT approaches display considerable potential to study positron binding to large molecules because of the fifth power scaling with respect to the number of basis sets. In this regard, we present additional PBE calculations of some small polar organic molecules, amino acids and DNA nucleobases. We complement our numerical assessment with formal and numerical analyses of the treatment of electron-positron correlation within the quasiparticle propagator approach.

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Section: Self-energy Approximationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation of positron binding energies using the generalized any particle propagator theory

Romero

Charry

Flores‐Moreno

et al. 2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The zerorange potential model [9,10] captured the qualitative features of the binding for alkanes and correctly predicted the emergence of the second bound state [9]. There were also predictions of positron binding to the hydrogen molecule in the excited A S u 3 state [11], and configuration interaction (CI) calculations for carbon-containing triatomics (CO 2 , CS 2 , CSe 2 and weakly polar COS, COSe and CSSe) [12,13]. The latter papers reported binding by the two heaviest species in the vibrational ground state, by CS 2 in the lowest vibrationally excited states, and by other molecules at higher vibrational excitations or upon bond deformations.…”

Section: Introductionmentioning

confidence: 74%

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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e+(PsH)2: A three-positron molecule with a positronic chemical bond

Bressanini

2022

The Journal of Chemical Physics

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Two new positronic molecules have been recently discovered: [Angew. Chem. Int. Ed. 57, 8859-8864 (2018)] and (PsH)2 [J. Chem. Phys. 155, 054306 (2021)]. These molecules seem to be stabilized by a new type of bond, the positronic bond, where one or two positrons are directly responsible for the bonding of two otherwise repelling negative ions. We show that a positron can attach to (PsH)2 to form a locally stable species with three positrons whose potential energy curve shows an equilibrium structure at about 8 bohr and a binding energy of 11.5(5) mhartree with respect to the dissociation into PsH + e+PsH. This molecule, tentatively called e+(PsH)2, is the first system with three positrons discovered.

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Positron attachment to theH2(A3

Cited by 5 publications

References 23 publications

Calculation of positron binding energies using the generalized any particle propagator theory

Calculation of positron binding energies using the generalized any particle propagator theory

Effect of dipole polarizability on positron binding by strongly polar molecules

e+(PsH)2: A three-positron molecule with a positronic chemical bond

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