The energetic stability of positron–dianion systems [Ae+; A] is studied via many-body theory, where A includes H, F, Cl, and the molecular anions (CN) and (NCO). Specifically, the energy of the system as a function of ionic separation is determined by solving the Dyson equation for the positron in the field of the two anions using a positron–anion self-energy as constructed in Hofierka et al. [Nature 606, 688 (2022)] that accounts for correlations, including polarization, screening, and virtual-positronium formation. Calculations are performed for a positron interacting with H22, F22, and Cl22 and are found to be in good agreement with previous theory. In particular, we confirm the presence of two minima in the potential energy of the [He+; H] system with respect to ionic separation: a positronically bonded [He+; H] local minimum at ionic separations r ∼ 3.4 Å and a global minimum at smaller ionic separations r ≲ 1.6 Å that gives overall instability of the system with respect to dissociation into a H2 molecule and a positronium negative ion, Ps. The first predictions are made for positronic bonding in dianions consisting of molecular anionic fragments, specifically for (CN)22 and (NCO)22. In all cases, we find that the molecules formed by the creation of a positronic bond are stable relative to dissociation into A and e+A (positron bound to a single anion), with bond energies on the order of 1 eV and bond lengths on the order of several ångstroms.

1.
J.
Charry
,
M. T. d. N.
Varella
, and
A.
Reyes
,
Angew. Chem., Int. Ed.
57
,
8859
(
2018
).
2.
M.
Goli
and
S.
Shahbazian
,
Chem. Phys. Chem
20
,
831
(
2019
).
3.
S.
Ito
,
D.
Yoshida
,
Y.
kita
, and
M.
Tachikawa
,
J. Chem. Phys.
153
,
224305
(
2020
).
4.
D.
Bressanini
,
J. Chem. Phys.
154
,
224306
(
2021
).
5.
F.
Moncada
,
L.
Pedraza-Gonzalez
,
J.
Charry
,
M. T.
do N. Varella
, and
A.
Reyes
,
Chem. Sci.
11
,
44
(
2019
).
6.
S.
Ito
,
D.
Yoshida
,
Y.
kita
,
T.
Shimazaki
, and
M.
Tachikawa
,
J. Chem. Phys.
158
,
204303
(
2023
).
7.
D.
Bressanini
,
J. Chem. Phys.
155
,
054306
(
2021
).
8.
D.
Schrader
,
Nucl. Instrum. Methods Phys. Res., Sect. B
143
,
209
(
1998
).
9.
J.
Charry
,
F.
Moncada
,
M.
Barborini
,
L.
Pedraza-González
,
M. T. do N.
Varella
,
A.
Tkatchenko
, and
A.
Reyes
,
Chem. Sci.
13
,
13795
(
2022
).
10.
J.
Hofierka
,
B.
Cunningham
,
C. M.
Rawlins
,
C. H.
Patterson
, and
D. G.
Green
,
Nature
606
,
688
(
2022
).
11.
J. P.
Cassidy
,
J.
Hofierka
,
B.
Cunningham
,
C. M.
Rawlins
,
C. H.
Patterson
, and
D. G.
Green
, “
Many-body theory calculations of positron binding to halogenated hydrocarbons
,” arXiv:2303.05359 [physics.chem-ph] (
2023
).
12.
J.
Hofierka
,
C. M.
Rawlins
,
B.
Cunningham
,
D. T.
Waide
, and
D. G.
Green
,
Front. Phys.
11
,
1227652
(
2023
).
13.
C. M.
Rawlins
,
J.
Hofierka
,
B.
Cunningham
,
C. H.
Patterson
, and
D. G.
Green
,
Phys. Rev. Lett.
130
,
263001
(
2023
).
14.

In this approximation, we account for positron–anion correlations but assume that the electron orbitals are unaffected by the presence of the positron. The good agreement we obtain with other methods suggests an a posteriori justification for this.

15.
V. A.
Dzuba
,
V. V.
Flambaum
,
G. F.
Gribakin
, and
W. A.
King
,
J. Phys. B: At., Mol. Opt. Phys.
29
,
3151
(
1996
).
16.
M.
Müller
and
L. S.
Cederbaum
,
Phys. Rev. A
42
,
170
(
1990
).
17.
G. F.
Gribakin
and
J.
Ludlow
,
Phys. Rev. A
70
,
032720
(
2004
).
18.
D. G.
Green
,
J. A.
Ludlow
, and
G. F.
Gribakin
,
Phys. Rev. A
90
,
032712
(
2014
).
19.
D. G.
Green
and
G. F.
Gribakin
,
Phys. Rev. A
88
,
032708
(
2013
).
20.
D. G.
Green
and
G. F.
Gribakin
,
Phys. Rev. Lett.
114
,
093201
(
2015
).
21.
A. L.
Fetter
and
J. D.
Walecka
,
Quantum Theory of Many-Particle Systems
(
Dover
,
New York
,
2003
).
22.
W. H.
Dickhoff
and
D. V.
Neck
,
Many-Body Theory Exposed!—Propagator Description of Quantum Mechanics in Many-Body Systems
, 2nd ed. (
World Scientific
,
Singapore
,
2008
).
23.
J.
Hofierka
,
B.
Cunningham
,
C. M.
Rawlins
, and
D.
Green
, “
Gaussian-basis many-body theory calculations of positron binding to negative ions and atoms
,” arXiv:2311.13066 (
2023
).
24.
R. A.
Kendall
,
T. H.
Dunning
, Jr.
, and
R. J.
Harrison
,
J. Chem. Phys.
96
,
6796
(
1992
).
25.
A. R.
Swann
and
G. F.
Gribakin
,
J. Chem. Phys.
149
,
244305
(
2018
).
26.
W.
Kolos
and
L.
Wolniewicz
,
J. Chem. Phys.
49
,
404
(
1968
).
27.
N.
Prantzos
,
C.
Boehm
,
A.
Bykov
,
R.
Diehl
,
K.
Ferrière
,
N.
Guessoum
,
P.
Jean
,
J.
Knoedlseder
,
A.
Marcowith
,
I.
Moskalenko
,
A.
Strong
, and
G.
Weidenspointner
,
Rev. Mod. Phys.
83
,
1001
(
2011
).
28.
T. J.
Millar
,
C.
Walsh
, and
T. A.
Field
,
Chem. Rev.
117
,
1765
(
2017
).
You do not currently have access to this content.