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Calculations of the positron binding energies to all atoms in the periodic table are presented and atoms where the positron-atom binding actually exists are identified. The results of these calculations and accurate calculations of other…

Atomic Physics · Physics 2015-06-16 C. Harabati , V. A. Dzuba , V. V. Flambaum

Many-body theory is developed to calculate the $\gamma$-spectra for positron annihilation with valence and core electrons in the noble gas atoms. A proper inclusion of correlation effects and core annihilation provides for an accurate…

Atomic Physics · Physics 2023-03-23 D. G. Green , G. F. Gribakin

$\gamma$ spectra for positron annihilation in noble-gas atoms are calculated using many-body theory for positron momenta up to the positronium-formation threshold. This data is used, together with time-evolving positron-momentum…

Atomic Physics · Physics 2017-11-22 D. G. Green

Calculations of the relaxation energy, contact pair-correlation function, and annihilating-pair momentum density for a single positron immersed in a homogeneous electron gas are presented. We achieve an accurate description of the…

Mesoscale and Nanoscale Physics · Physics 2011-01-20 N. D. Drummond , P. Lopez Rios , C. J. Pickard , R. J. Needs

A method is proposed for detecting positron-atom bound states by observing enhanced positron annihilation due to electronic Feshbach resonances at electron-volt energies. The method is applicable to a range of open-shell transition metal…

Atomic Physics · Physics 2010-12-10 V. A. Dzuba , V. V. Flambaum , G. F. Gribakin

The recently developed ab initio many-body theory of positron molecule binding [J. Hofierka et al., Nature, 606, 688 (2022)] is combined with the shifted pseudostates method [A. R. Swann and G. F. Gribakin, Phys. Rev. A 101, 022702 (2020)]…

Atomic Physics · Physics 2023-07-11 C. M. Rawlins , J. Hofierka , B. Cunningham , C. H. Patterson , D. G. Green

Para positronium composed by an electron-antielectron pair is an unstable system decaying into two high energetic gamma photons via self annihilation process, due to the conservation of the charge conjugation parity in electromagnetically…

Quantum Physics · Physics 2019-08-23 Abdullah Guvendi , Yusuf Sucu

The present study shows that the positrophilic electrons of a molecule dock into the positron attractive potential region in the annihilation process under the plane-wave approximation. The positron-electron annihilation processes of both…

Atomic and Molecular Clusters · Physics 2015-06-15 Xiaoguang Ma , Feng Wang

This paper is devoted to study many-body effects in the positron annihilation experiment, both electron-positron (e-p) and electron-electron (e-e) correlations. Various theories of the e-p interaction in real solids were used to verify them…

Materials Science · Physics 2007-05-23 G. Kontrym-Sznajd , H. Sormann

A simultaneous analysis of high-resolution directional Compton profiles and two-dimensional angular correlation of positron annihilation experimental data has been performed by studying both a directional anisotropy of measured spectra and…

In the article by Ma~\emph{et al.}~[Phys.~Rev.~A {\bf 94}, 052709 (2016)], $\gamma$-ray spectra for positron annihilation on molecules were calculated in the independent-particle approximation with the positron wavefunction set to unity.…

Atomic Physics · Physics 2017-03-22 D. G. Green , G. F. Gribakin

Positron binding energies in halogenated hydrocarbons are calculated \emph{ab initio} using many-body theory. For chlorinated molecules, including planars for which the interaction is highly anisotropic, very good to excellent agreement…

Chemical Physics · Physics 2024-04-24 J. P. Cassidy , J. Hofierka , B. Cunningham , C. M. Rawlins , C. H. Patterson , D. G. Green

Bound electron contribution to the Doppler-shift of gamma-ray spectra in the positron-electron annihilation process of molecular methane has been studied in gas phase. Two accurate ab initio quantum mechanical schemes, i.e. the delocalized…

Atomic Physics · Physics 2013-04-01 Xiaoguang Ma , Feng Wang

Halide perovskites have emerged in the last decade as a new important class of semiconductors for a variety of optoelectronic applications. A lot of previous studies were thus devoted to the characterisation of their point defects. Positron…

Materials Science · Physics 2026-04-23 Kajal Madaan , Guido Roma , Jasurbek Gulomov , Pascal Pochet , Catherine Corbel , Ilja Makkonen

The correlated motion of a positron surrounded by electrons is a fundamental many-body problem. We approach this by modeling the momentum density of annihilating electron-positron pairs using the framework of reduced density matrices,…

Strongly Correlated Electrons · Physics 2014-01-13 Ilja Makkonen , Mikko M. Ervasti , Topi Siro , Ari Harju

The many-body-theory approach to positronium-atom interactions developed in [Phys. Rev. Lett. \textbf{120}, 183402 (2018)] is applied to the sequence of noble-gas atoms He-Xe. The Dyson equation is solved separately for an electron and…

Atomic Physics · Physics 2023-05-24 A. R. Swann , D. G. Green , G. F. Gribakin

Mijnarends et al. [J. Phys. Condens. Matter {\bf 10}, 10383 (1998)] contested the best existing calculations of positron annihilation rates in jellium and crystal lattices, pointing in this way at deficiencies of existing theories of…

Soft Condensed Matter · Physics 2007-05-23 H. Stachowiak , E. Boronski

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…

Atomic Physics · Physics 2015-09-24 G. F. Gribakin , A. R. Swann

We investigate positron annihilation in electron liquid as a case study for many-body theory, in particular the optimized Fermi Hypernetted Chain (FHNC-EL) method. We examine several approximation schemes and show that one has to go up to…

Condensed Matter · Physics 2010-09-24 V. Apaja , S. Denk , E. Krotscheck

A problem to account for the direct electron-positron annihilation in positron-hydrogen scattering above the positronium formation threshold has been resolved within the time independent formalism. The generalization of the optical theorem…

Atomic Physics · Physics 2011-02-03 S L Yakovlev , C-Y Hu , D Caballero