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Microscopic kinetics in poly(Methyl methacrylate) exposed to a single ultra-short xuv/x-ray laser pulse
- 1.0548840 - ÚFP 2022 RIV CH eng J - Journal Article
Medvedev, Nikita - Chalupský, J. - Juha, L.
Microscopic kinetics in poly(Methyl methacrylate) exposed to a single ultra-short xuv/x-ray laser pulse.
Molecules. Roč. 26, č. 21 (2021), č. článku 6701. E-ISSN 1420-3049
R&D Projects: GA MŠMT LTT17015
Institutional support: RVO:61389021
Keywords : Ablation * Band gap collapse * Free-electron laser * Nonthermal melting * pmma
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 4.927, year: 2021
Method of publishing: Open access
https://www.mdpi.com/1420-3049/26/21/6701
We study the behavior of poly(methyl methacrylate) (PMMA) exposed to femtosecond pulses of extreme ultraviolet and X-ray laser radiation in the single-shot damage regime. The employed microscopic simulation traces induced electron cascades, the thermal energy exchange of electrons with atoms, nonthermal modification of the interatomic potential, and a triggered atomic response. We identify that the nonthermal hydrogen decoupling triggers ultrafast fragmentation of PMMA strains at the absorbed threshold dose of ~0.07 eV/atom. At higher doses, more hydrogen atoms detach from their parental molecules, which, at the dose of ~0.5 eV/atom, leads to a complete separation of hydrogens from carbon and oxygen atoms and fragmentation of MMA molecules. At the dose of ~0.7 eV/atom, the band gap completely collapses indicating that a metallic liquid is formed with complete atomic disorder. An estimated single-shot ablation threshold and a crater depth as functions of fluence agree well with the experimental data collected.
Permanent Link: http://hdl.handle.net/11104/0324888
Number of the records: 1