Skip to Main content Skip to Navigation
Journal articles

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

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.
Complete list of metadata

https://hal-cea.archives-ouvertes.fr/cea-03552249
Contributor : Contributeur MAP CEA Connect in order to contact the contributor
Submitted on : Wednesday, February 2, 2022 - 11:06:56 AM
Last modification on : Saturday, February 5, 2022 - 3:33:08 AM
Long-term archiving on: : Tuesday, May 3, 2022 - 6:46:28 PM

File

qi_bruneval_maliyov_PhysRevLet...
Publisher files allowed on an open archive

Identifiers

Citation

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

Share

Metrics

Record views

16

Files downloads

70