Microscopic kinetics in poly(methyl methacrylate) exposed to a single ultra-short XUV/X-ray laser pulse

0547891 - FZÚ 2022 RIV CH eng J - Článek v odborném periodiku
Medvedev, Nikita - Chalupský, Jaromír - Juha, Libor
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
Grant CEP: GA MŠMT(CZ) EF18_053/0016627; GA MŠMT LTT17015; GA ČR(CZ) GA20-08452S
Grant ostatní: OP VVV - Mobility FZU 2(XE) CZ.02.2.69/0.0/0.0/18_053/0016627
Výzkumná infrastruktura: e-INFRA CZ - 90140
Klíčová slova: PMMA * free-electron laser * ablation * nonthermal melting * band gap collapse
Obor OECD: Optics (including laser optics and quantum optics)
Impakt faktor: 4.927, rok: 2021
Způsob publikování: Open access

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 agree well with the experimental data collected.

Trvalý link: http://hdl.handle.net/11104/0324055