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Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have uncovered a key step in the ionization of liquid water using the lab’s high-speed “electron camera,” MeV-UED. This reaction is of fundamental significance to a wide range of fields, including nuclear engineering, space travel, cancer treatment and environmental remediation. Their results were published in Science today. When high-energy radiation hits a water molecule, it triggers a series of ultrafast reactions. First, it kicks out an electron, leaving behind a positively charged water molecule. Within a fraction of a trillionth of a second, this water molecule gives up a proton to another water molecule. This leads to the creation of a hydroxyl radical (OH) – which can damage virtually any macromolecule in an organism, including DNA, RNA and proteins – and a hydronium ion (H3O+), which are abundant in the interstellar medium and tails of comets, and might contain clues about the origin of life. More details can be found here.

Structure retrieval in liquid-phase electron scattering Electron scattering on liquid samples has been enabled recently by the development of ultrathin liquid sheet technologies. The data treatment of liquid-phase electron scattering has been mostly reliant on methodologies developed for gas electron diffraction, in which theoretical inputs and empirical fittings are often needed to account for the atomic form factor and remove the inelastic scattering background. In this work, we present an alternative data treatment method that is able to retrieve the radial distribution of all thecharged particle pairs without the need of either theoretical inputs or empirical fittings. The merits of this new method are illustrated through the retrieval of real-space molecular structure from experimental electron scattering patterns of liquid water, carbon tetrachloride, chloroform, and dichloromethane. The source can be found here.

Direct observation of ultrafast hydrogen bond strengthening in liquid water Water is one of the most important, yet least understood, liquids in nature. Many anomalous properties of liquid water originate from its well-connected hydrogen bond network, including unusually efficient vibrational energy redistribution and relaxation. An accurate description of the ultrafast vibrational motion of water molecules is essential for understanding the nature of hydrogen bonds and many solution-phase chemical reactions. Most existing knowledge of vibrational relaxation in water is built upon ultrafast spectroscopy experiments. However, these experiments cannot directly resolve the motion of the atomic positions and require difficult translation of spectral dynamics into hydrogen bond dynamics. Here, we measure the ultrafast structural response to the excitation of the OH stretching vibration in liquid water with femtosecond temporal and atomic spatial resolution using liquid ultrafast electron scattering. We observed a transient hydrogen bond contraction of roughly 0.04 Å on a timescale of 80 femtoseconds, followed by a thermalization on a timescale of approximately 1 picosecond. Molecular dynamics simulations reveal the need to treat the distribution of the shared proton in the hydrogen bond quantum mechanically to capture the structural dynamics on femtosecond timescales. Our experiment and simulations unveil the intermolecular character of the water vibration preceding the relaxation of the OH stretch. Read more here.

Generation and characterization of ultrathin free-flowing liquid sheets The physics and chemistry of liquid solutions play a central role in science, and our understanding of life on Earth. Unfortunately, key tools for interrogating aqueous systems, such as infrared and soft X-ray spectroscopy, cannot readily be applied because of strong absorption in water. Here we use gas-dynamic forces to generate free-flowing, sub-micron, liquid sheets which are two orders of magnitude thinner than anything previously reported. Optical, infrared, and X-ray spectroscopies are used to characterize the sheets, which are found to be tunable in thickness from over 1 μm  down to less than 20 nm, which corresponds to fewer than 100 water molecules thick. At this thickness, aqueous sheets can readily transmit photons across the spectrum, leading to potentially transformative applications in infrared, X-ray, electron spectroscopies and beyond. The ultrathin sheets are stable for days in vacuum, and we demonstrate their use at free-electron laser and synchrotron light sources. Read more here.

It’s difficult to give a real advice regarding the film degasser. The film degasser will not replace the need for a good start-up protocol that limits the amount of air inside the tubing and chip. It crucial to prefill the fluidic lines and flush before placing the chip inside the holder.When a film degasser is placed just before the chip it might help to trap and remove bubbles that where still in the system and might become loos at some moment in time. Mostly the effect of gasses inside the liquids is limited when the liquid is not oversaturated. I would also be possible to adjust the saturation of gasses inside the liquid by placing a open reservoir under a vacuum hood upfront a experiment. Liquid sheet can be very thin, they can reach a thickness of just a few molecules in this situation it makes, besides the impact of a gas molecule on sheet stability, a lot of difference if you are looking at gas or liquid molecule. It would be well recommended to consider limiting the gas saturation in the experiment.

Wet etched structures are extremely smooth and have a roughness in Angstrom range. The structures are fully optical transparent. Large roughness for structures in glass chips is typical observed for structures manufactured by use of laser assisted manufacturing techniques or abrasion-based techniques like powder blasting. Almost all catalogue products from Micronit are manufactured using wet etching to create full transparent channels without substantial roughness.