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Not AvailableSoft-solid molecular crystals consist of crystalline grains and fluid grain boundaries (GB) that enhance the grain binding and transport of Li+ ions between the grains. The total ionic conductivity consists of ion migration in both the grains and GBs. To unravel these contributions in adiponitrile (Adpn):LiPF6 molecular crystals, the GB volume fraction was varied by changing the size of the crystals and the Adpn:LiPF6 molar ratio. Molecular dynamic (MD) simulations indicate that ion motion was sub-diffusive in the grains and “well-diffusive” in the GBs, with GBs characterized as disordered nano-confined regions of higher charge carrier concentration (~1M) than in saturated Adpn:LiPF6 solutions (0.04M), and ions predominantly solvated by -C≡N groups with few contact ion pairs. The diffusivity in the GBs is at least an order of magnitude higher than in the crystalline grains. The emergent picture is the grains as a reservoir of ions that migrate to the faster-conducting GBs. 

Assisted by predictions from density functional theory, we used infrared spectroscopy to observe hydride ions introduced into SrTiO3 crystals. 

Abstract Over geologic time‐scales, large volumes of exogenic sulfur ions from Io's plasma torus have been supplied to the surface of Europa and Ganymede, which, combined with recent interpretations of orbiter images, dynamical modeling, and surface‐subsurface exchange, suggests further sulfur transport into the interior of the icy worlds. These observations motivate mixed‐phase spectral modeling for interpreting orbiter spectroscopy data and determination of hydration states of candidate surface materials including hydrous sulfates. In this work, we present a combined experimental and theoretical study of the low temperature and high pressure vibrational spectral signature of the iron‐sulfate monohydrate endmember, szomolnokite (FeSO₄·H₂O). By employing synchrotron Fourier‐transform infrared spectroscopy (FTIR) in the diamond anvil cell up to 23 GPa and down to 20 K, we explore the extreme range of pressure‐temperature domains relevant to icy environments throughout our solar system and beyond. Combined with our density‐functional theory quantum‐mechanics molecular dynamics results, we demonstrate that experimentally observed infrared features in the O‐H stretching region commonly associated withnH₂O (n > 1) hydration states can be attributed to a pure monohydrate without the need for pressure‐induced exsolved ice, other coexisting hydrous iron sulfates, or strong overtone and combination modes. We further discuss the possibility of lateral variations in density and shear properties on icy worlds associated with temperature variations and the high‐pressure phases of kieserite group monohydrated sulfates. 

Dipoles are ubiquitous, and their impacts on materials and interfaces affect many aspects o fdaily life. Despite their importance, dipoles remain underutilized, often because of insufficient knowledge about the structures producing them. As electrostatic analogues of magnets, electrets possess ordered electric dipoles. Here, we characterize the structural dynamics of bioinspired electret oligomers based on anthranilamide motifs. We report dynamics simulations, employing a force field that allows dynamic polarization, in a variety of solvents. The results show a linear increase in macrodipoles with oligomer length that strongly depends on solvent polarity and hydrogen-bonding (HB) propensity, as well as on the anthranilamide side chains. An increase in solvent polarity increases the dipole moments of the electret structures while decreasing the dipole effects on the moieties outside the solvation cavities. The former is due to enhancement of the Onager reaction field and the latter to screening of the dipole-generated fields. Solvent dynamics hugely contributes to the fluctuations and magnitude of the electret dipoles. HB with the solvent weakens electret macrodipoles without breaking the intramolecular HB that maintains their extended conformation. This study provides design principles for developing a new class of organic materials with controllable electronic properties.