Ab initio prediction of a negative Barkas coefficient for slow protons and antiprotons in LiF - Archive ouverte HAL Access content directly
Journal Articles Physical Review Letters Year : 2022

Ab initio prediction of a negative Barkas coefficient for slow protons and antiprotons in LiF

(1) , (1) , (2)
1
2

Abstract

We report the \textit{ab initio} prediction of a negative Barkas coefficient in LiF insulator at low velocity (v< 0.25 a.u. ~ 2 keV). The electronic stopping power of protons in lithium fluoride has been extensively studied both experimentally and theoretically because of a controversial threshold effect. While our time-dependent density-functional theory (TDDFT) simulations confirm the presence of a velocity threshold below which the proton stopping power vanishes, our calculations demonstrate that the antiprotons do not experience such a threshold. The combination of those two contrasting behaviors gives rise to an unprecedented negative Barkas effect: the stopping power of antiprotons is larger than that of protons. We identify that the slow antiproton at close encounter destabilizes a p orbital of the F- anion pointing towards the antiproton. This particular orbital becomes highly polarizable and hence contributes much to the stopping power.
Fichier principal
Vignette du fichier
qi_bruneval_maliyov_PhysRevLett2022.pdf (567.26 Ko) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

cea-03552249 , version 1 (02-02-2022)

Identifiers

Cite

Xixi Qi, Fabien Bruneval, Ivan Maliyov. Ab initio prediction of a negative Barkas coefficient for slow protons and antiprotons in LiF. Physical Review Letters, 2022, 128 (4), pp.043401. ⟨10.1103/PhysRevLett.128.043401⟩. ⟨cea-03552249⟩
21 View
94 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More