Observation of electron transfer mediated decay in aqueous solution

Photoionization is at the heart of X ray photoelectron spectroscopy XPS , which gives access to important information on a sample s local chemical environment. Local and non local electronic decay after photoionization in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively have been well studied. However, electron transfer mediated decay ETMD , which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase. Here we report the experimental observation of ETMD in an aqueous LiCl solution by detecting characteristic secondary low energy electrons using liquid microjet soft XPS. Experimental results are interpreted using molecular dynamics and high level ab initio calculations. We show that both solvent molecules and counterions participate in the ETMD processes, and different ion associations have distinctive spectral fingerprints. Furthermore, ETMD spectra are sensitive to coordination numbers, ion solvent distances and solvent arrangemen

Carbon Dioxide Diffusion and Plasticization in Fluorinated Polyimides

status: publishe

Carbon Dioxide Solubility in Three Fluorinated Polyimides Studied by Molecular Dynamics Simulations

status: publishe

Atomistic Models of Three Fluorinated Polyimides in the Amorphous State

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Ultralow-k dielectrics made by supercritical foaming of thin polymer films

Ultralow dielectric constants have been achieved for thin porous films of high-T-g polymers. Rapid solid-state polymer expansion applying supercritical carbon dioxide was used to create nanosized cavities in thin films of aromatic polyimides (see Figure). Foamed films with spherical voids less than 10 nm in size as well as multilayered microstructures with interlayer distances of less than 20 nm were made with k values as low as 1.77.status: publishe