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We analyzed the Hartree-Fock approximation for an electron system. The interaction between particles is modeled by a non-Coulombian potential. We analyzed both the three-dimensional and two-dimensional systems. We obtained accurate…

Quantum Gases · Physics 2024-08-28 Vlad-Mihai Ene , Ilinca Lianu , Ioan Grosu

While the exact total energy of a separated open system varies linearly as a function of average electron number between adjacent integers, the energy predicted by semi-local density functional approximations curves upward and the…

Extending density functional theory (DFT) to an {\it ab initio} orbital functional theory (OFT) requires new methodology for nonlocal exchange and correlation potentials. This paper describes such modifications to a standard Dirac-Slater…

Condensed Matter · Physics 2007-05-23 R. K. Nesbet

External non-uniform magnetic fields acting on molecules induce non-collinear spin-densities and spin-symmetry breaking. This necessitates a general two-component Pauli spinor representation. In this paper, we report the implementation of a…

Chemical Physics · Physics 2018-05-23 Sangita Sen , Erik I. Tellgren

In this study, a fully self-consistent method was developed to obtain the wave functions of the positron and electrons in molecules simultaneously. The wave function of a positron at room temperature , with a characteristic energy of…

Atomic and Molecular Clusters · Physics 2020-06-24 Lin Tang , Xiaoguang Ma , Jipeng Sui , Meishan Wang , Chuanlu Yang

The differential cross-section of the single-photon annihilation of channeled positron on the K-shell electron of one of the crystal atoms is calculated and angular distribution of emitted photons is investigated. It is shown that…

Quantum Physics · Physics 2022-01-13 K. B. Korotchenko , Y. P. Kunashenko

We investigated the out-of-plane transport properties of parent and chemically substituted BaFe$_{2}$As$_{2}$ for various types of substitution. Based on the studies of Hall coefficient and chemical-substitution effect, we have clarified…

Superconductivity · Physics 2021-03-18 Masamichi Nakajima , Masahiko Nagafuchi , Setsuko Tajima

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

We show that the electric field-induced thermal asymmetry between the electron and lattice systems in pure silicon substantially impacts the identity of the dominant spin relaxation mechanism. Comparison of empirical results from…

Materials Science · Physics 2012-04-10 Jing Li , Lan Qing , Hanan Dery , Ian Appelbaum

We demonstrate that the angular distribution of electrons knocked out from an atom by a fast charge particle is determined not only by dipole but also by quadrupole transitions, the contribution of which can be considerably enhanced as…

Atomic Physics · Physics 2010-12-30 M. Ya. Amusia , L. V. Chernysheva , E. Z. Liverts

Electron correlation effects play a key role in stabilising two-electron atoms near the critical nuclear charge, representing the smallest charge required to bind two electrons. However, deciphering the importance of these effects relies on…

Chemical Physics · Physics 2021-03-31 Hugh G. A. Burton

We present evidence for small oscillations we observe in electron-positron and proton-antiproton annihilation data, with a periodicity of 76+-2 MeV, independent of the beam energy. We discuss some possible scenarios to explain the…

High Energy Physics - Phenomenology · Physics 2010-09-28 Eef van Beveren , George Rupp

Symmetric electron-positron plasmas in inhomogeneous magnetic fields are intrinsically subject to interchange instability and transport. Scaling relations for the propagation velocity of density blob perturbations relevant to transport in…

Plasma Physics · Physics 2017-06-14 Alexander Kendl , Gregor Danler , Matthias Wiesenberger , Markus Held

Standard density functional approximations greatly over-estimate the static polarizability of longchain polymers, but Hartree-Fock or exact exchange calculations do not. Simple self-interaction corrected (SIC) approximations can be even…

Atomic and Molecular Clusters · Physics 2007-08-22 C. D. Pemmaraju , S. Sanvito , K. Burke

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

In the Milky Way galaxy, positrons, which are responsible for the diffuse $511\,\mathrm{keV}$ gamma ray emission observed by space-based gamma ray observatories, are thought to annihilate predominantly through charge exchange interactions…

High Energy Astrophysical Phenomena · Physics 2018-08-15 Fiona H. Panther , Ivo R. Seitenzahl , Roland M. Crocker , Joshua R. Machacek , Dan J. Murtagh , Thomas Siegert , Roland Diehl

Fractional-spin errors are inherent in all current approximate density functionals, including Hartree-Fock theory, and their origin has been related to strong static correlation effects. The conventional way to encode fractional-spin…

Shuttle-like mechanism of electron transport through a single level vibrating quantum dot is considered in the regime of strong electromechanical coupling. It is shown that the increment of shuttle instability is a nonmonotonic function of…

Mesoscale and Nanoscale Physics · Physics 2013-02-07 Gleb A. Skorobagatko , Ilya V. Krive , Robert I. Shekhter

We investigate the properties of norm-conserving pseudopotentials (effective core potentials) generated by inversion of the Hartree-Fock equations. In particular we investigate the asymptotic behaviour as $\mathbf{r} \to \infty$ and find…

Materials Science · Physics 2009-10-01 J. R. Trail , R. J. Needs

Evolutions of single-particle energies and Z=64 sub-shell along the isotonic chain of N=82 are investigated in the density dependent relativistic Hartree-Fock (DDRHF) theory in comparison with other commonly used mean field models such as…

Nuclear Theory · Physics 2009-10-07 Wen Hui Long , Takashi Nakatsukasa , Hiroyuki Sagawa , Jie Meng , Hitoshi Nakada , Ying Zhang