An interplay of various damage channels in polyethylene exposed to ultra-short XUV/X-ray pulses

0579467 - ÚFP 2024 RIV GB eng J - Journal Article
Medvedev, Nikita - Babaev, P. - Chalupský, J. - Juha, Libor - Volkov, A.E.
An interplay of various damage channels in polyethylene exposed to ultra-short XUV/X-ray pulses.
Physical Chemistry Chemical Physics. Roč. 23, č. 30 (2021), s. 16193-16205. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA MŠMT LTT17015; GA MŠMT(CZ) LM2018114; GA ČR(CZ) GA20-08452S
EU Projects: European Commission(XE) 871124 - LASERLAB-EUROPE
Grant - others:Ministerstvo školství, mládeže a tělovýchovy - GA MŠk(CZ) LM2018140; European Cooperation in Science and Technology(BE) CA17126
Program: COST
Institutional support: RVO:61389021
Keywords : polyethylene * X-ray * XUV
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 3.945, year: 2021
Method of publishing: Limited access
https://pubs.rsc.org/en/content/articlelanding/2021/CP/D1CP02199K

Polyethylene (PE) irradiated with femtosecond extreme ultraviolet or X-ray laser pulses in a single-shot damage regime is studied theoretically. The employed microscopic simulation tool XTANT-3 traces nonequilibrium electron kinetics, energy exchange between electrons and atoms, nonthermal modification of interatomic potential, and the induced atomic response. It is found that the nonthermal detachment of hydrogen atoms in bulk PE starts at the threshold deposited dose of ∼0.05 eV per atom. With an increase in the dose, more hydrogen atoms detach from the carbon backbone. At a dose of ∼0.3 eV per atom, hydrogen behaves like a liquid flowing around carbon chains. It is accompanied by the appearance of defect energy levels within the band gap. At a dose of ∼0.5 eV per atom, carbon chains actively bend and cross-link. In the range of doses from ∼0.5 eV per atom to ∼0.9 eV per atom, the electronic excitation induces formation of new carbon structures embedded in the hydrogen liquid, such as benzene-like rings. The band gap collapses at such doses, merging the valence and the conduction bands. Finally, at doses above ∼0.9 eV per atom, the carbon subsystem also melts into liquid. All of these damage mechanisms are mainly nonthermal, triggered by promotion of electrons from the valence into the conduction band of PE. At high doses, however, thermal electron-ion coupling is extremely fast causing equilibration of the electronic and the ionic temperatures within a hundred femtoseconds.
Permanent Link: https://hdl.handle.net/11104/0348304