Many atoms and negative ions are able to bind a positron. Their structure consists of an atomic core with an orbiting positron or positronium (Ps). A few systems can also bind two positrons, but much less is known about their internal structure. We examine the family pen-em+ with a proton p, n≤4 electrons, and m≤2 positrons. Using quantum Monte Carlo techniques, we study the energetics and structure of pe4-e2+. We compute its ground-state energy [-1.05910(1) hartree] and its binding energy (0.0079 hartree). We show that to construct a bound variational wave function, despite having a single nucleus, we must adopt a molecular description of this system, using HPs, Ps-, H-, and Ps2 as interacting fragments. The analysis of the electronic and positronic probability distributions reveals that at zero order, the internal structure of this system consists of a Ps- interacting with the HPs core. Based on these results, we speculate about the existence of similar systems containing three positrons. © 2019 American Physical Society.

Energetics and structure of Ps-HPs using a molecular approach

Bressanini, D.
2019-01-01

Abstract

Many atoms and negative ions are able to bind a positron. Their structure consists of an atomic core with an orbiting positron or positronium (Ps). A few systems can also bind two positrons, but much less is known about their internal structure. We examine the family pen-em+ with a proton p, n≤4 electrons, and m≤2 positrons. Using quantum Monte Carlo techniques, we study the energetics and structure of pe4-e2+. We compute its ground-state energy [-1.05910(1) hartree] and its binding energy (0.0079 hartree). We show that to construct a bound variational wave function, despite having a single nucleus, we must adopt a molecular description of this system, using HPs, Ps-, H-, and Ps2 as interacting fragments. The analysis of the electronic and positronic probability distributions reveals that at zero order, the internal structure of this system consists of a Ps- interacting with the HPs core. Based on these results, we speculate about the existence of similar systems containing three positrons. © 2019 American Physical Society.
2019
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062279268&doi=10.1103/PhysRevA.99.022510&partnerID=40&md5=ebc2b19166038f8ccb05e67f1588a137
Bressanini, D.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2095644
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