期刊
MOLECULES
卷 26, 期 21, 页码 -出版社
MDPI
DOI: 10.3390/molecules26216701
关键词
PMMA; free-electron laser; ablation; nonthermal melting; band gap collapse
资金
- Czech Ministry of Education, Youth and Sports [e-INFRA LM2018140, LTT17015]
- Czech Science Foundation [20-08452S]
- EU funded COST Action [CA17126]
- [LM2015083]
The study investigates the behavior of PMMA exposed to femtosecond pulses of extreme ultraviolet and X-ray laser radiation, revealing the nonthermal hydrogen decoupling triggering ultrafast fragmentation of PMMA and the formation of a metallic liquid with complete atomic disorder as the dose increases. The estimated ablation threshold and crater depth functions of fluence align well with experimental data.
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.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据