Publications by authors named "Thomas M Linker"
Since the invention of the laser, nonlinear effects such as filamentation, Rabi cycling and collective emission have been explored in the optical regime, leading to a wide range of scientific and industrial applications. X-ray free-electron lasers (XFELs) have extended many optical techniques to X-rays for their advantages of ångström-scale spatial resolution and elemental specificity. An example is XFEL-driven inner-shell Kα (2p → 1s) X-ray lasing in elements ranging from neon to copper, which has been used for nonlinear spectroscopy and development of new X-ray laser sources.
View Article and Find Full Text PDFHigh electric fields can significantly alter catalytic environments and the resultant chemical processes. Such fields arise naturally in biological systems but can also be artificially induced through localized nanoscale excitations. Recently, strong field excitation of dielectric nanoparticles has emerged as an avenue for studying catalysis in highly ionized environments, producing extreme electric fields.
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- Surface charges are crucial in determining the catalytic properties of nanomaterials, but studying their dynamics at the nanoscale is difficult due to varying length and time scales.
- This study utilizes reaction nanoscopy to visualize charge dynamics on individual SiO nanoparticles with femtosecond and nanometer resolution, revealing how surface charges redistribute over time.
- The research enhances our understanding of how surface charges affect chemical bonding on a nanoscale level, which could have significant implications for renewable energy and advanced healthcare innovations.*
We have developed an extension of the Neural Network Quantum Molecular Dynamics (NNQMD) simulation method to incorporate electric-field dynamics based on Born effective charge (BEC), called NNQMD-BEC. We first validate NNQMD-BEC for the switching mechanisms of archetypal ferroelectric PbTiO bulk crystal and 180° domain walls (DWs). NNQMD-BEC simulations correctly describe the nucleation-and-growth mechanism during DW switching.
View Article and Find Full Text PDFMetal-fullerene compounds are characterized by significant electron transfer to the fullerene cage, giving rise to an electric dipole moment. We use the method of electrostatic beam deflection to verify whether such reactions take place within superfluid helium nanodroplets between an embedded C molecule and either alkali (heliophobic) or rare-earth (heliophilic) atoms. The two cases lead to distinctly different outcomes: CNa ( = 1-4) display no discernable dipole moment, while CYb is strongly polar.
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- Organic polymers are flexible and cost-effective dielectric materials but struggle with breakdown under high electric fields, unlike inorganic materials.
- Dielectric breakdown in polymers is poorly understood, particularly the mechanisms that lead to it, contrasting with the known processes in inorganic dielectrics.
- The study utilizes quantum molecular dynamics simulations to investigate how high electric fields affect hot carrier behavior and chemical damage in polyethylene, revealing a critical transition that could help predict polymers with higher breakdown fields.