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Category: chemistry – Page 17

In a new study, EPFL scientists visualized the intricate interplay between electron dynamics and solvent polarization in this process. This is a significant step in understanding a critical process of many chemical phenomena, and it might be the first step to improving energy conversion technologies.

CTTS is like a dance of microbes where one electron from a dissolved material (like salt) emerges and becomes part of the water. This produces a “hydrated” electron, essential for several watery processes, including those necessary for life. Comprehending CTTS is crucial to understanding the motion of electrons in solutions.

In a recent study, EPFL researchers Jinggang Lan, Majed Chergui, and Alfredo Pasquarello examined the complex interactions between electrons and their solvent surroundings. The work was mostly done at EPFL, with Jinggang Lan’s final contributions made while he was a postdoctoral fellow at the Simons Center for Computational Physical Chemistry at New York University.

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Now, a new study combines meteorite data with thermodynamic modeling and determines that the earliest inner solar system planetesimals must have formed in the presence of water, challenging current astrophysical models of the early solar system.

Researchers study iron meteorites as samples from the early solar system. These meteorites represent the metallic cores of the earliest planetesimals that didn’t become planets but orbited the solar system before reaching Earth. By analyzing the chemical compositions of these meteorites, scientists can learn about the conditions in which they formed.

This helps answer questions about whether Earth’s building blocks formed far from the Sun, allowing the existence of water ice, or closer to the Sun, resulting in dry planetesimals. Even though the meteorites don’t contain water, scientists can deduce its past presence by examining its effects on other chemical elements.

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Density functional theory (DFT) is a cornerstone tool of modern physics, chemistry, and engineering used to explore the behavior of electrons. While essential in modeling systems with many electrons, it suffers from a well-known flaw called self-interaction error. A recent study has identified a new area where a correction for this error breaks down.

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The ultrafast dynamics and interactions of electrons in molecules and solids have long remained hidden from direct observation. For some time now, it has been possible to study these quantum-physical processes—for example, during chemical reactions, the conversion of sunlight into electricity in solar cells and elementary processes in quantum computers—in real time with a temporal resolution of a few femtoseconds (quadrillionths of a second) using two-dimensional electronic spectroscopy (2DES).

However, this technique is highly complex. Consequently, it has only been employed by a handful of research groups worldwide to date. Now a German-Italian team led by Prof. Dr. Christoph Lienau from the University of Oldenburg has discovered a way to significantly simplify the experimental implementation of this procedure. “We hope that 2DES will go from being a methodology for experts to a tool that can be widely used,” explains Lienau.

Two doctoral students from Lienau’s Ultrafast Nano-Optics research group, Daniel Timmer and Daniel Lünemann, played a key role in the discovery of the new method. The team has now published a paper in Optica describing the procedure.

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Oxygen is essential for life and a reactive player in many chemical processes. Accordingly, methods that accurately measure oxygen are relevant for numerous industrial and medical applications: They analyze exhaust gases from combustion processes, enable the oxygen-free processing of food and medicines, monitor the oxygen content of the air we breathe or the oxygen saturation in blood.

Oxygen analysis is also playing an increasingly important role in .

“However, such measurements usually require bulky, power-hungry, and expensive devices that are hardly suitable for mobile applications or continuous outdoor use,” says Máté Bezdek, Professor of Functional Coordination Chemistry at ETH Zurich. His group uses molecular design methods to find new sensors for environmental gases.

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An artificial nerve that is based on a vertical n-type organic electrochemical transistor with a gradient-intermixed bicontinuous structure can operate at high frequencies and mimic basic conditioned reflex behaviour in animals.

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The shape is another important morphological feature that matters as a critical aspect of nanotoxicity. Studies have shown that shape plays a role in determining the cellular uptake of micro-nano particles (65, 66). SRS images of plastic particles confirmed the existence of shape diversity for micro-nano plastics in bottled water. To account for the shape of plastic particles in a statistical manner, we measure the aspect ratio of individual particles above the diffraction limit (Fig. 6 H). The aspect ratio is widely acknowledged in nanotoxicology studies (67, 68). The aspect ratio of the plastic particles detected ranges from 1 to 6, and the average aspect ratio for particles is around 1.7. Fig. 6 I–M provides a pictorial view of how the aspect ratio is related to the particle shape. Particles with an aspect ratio of above 3 are most likely to be fibrous in shape, while particles with an aspect ratio of below 1.4 will be largely spherical. Shape variation on plastic particles has been found in all polymers detected, confirming the widely recognized idea that real-world micro-nano plastics have diverse morphological prosperities. This dimension is hard to be resembled by engineered polymer nanoparticles commonly studied in research laboratories, and the toxicological consequences pertaining to real-life plastic particle exposures and their differing physicochemical properties (i.e., size, shape) have yet to be determined.

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It’s about my paper.

Dissolving polymers with organic solvents is the essential process in the research and development of polymeric materials, including polymer synthesis, refining, painting, and coating. Now more than ever recycling plastic waste is a particularly imperative part of reducing carbon produced by the materials development processes.

Polymers, in this instance, refer to plastics and plastic-like materials that require certain solvents to be able to effectively dissolve and therefore become recyclable, though it’s not as easy as it sounds. Utilizing Mitsubishi Chemical Group’s (MCG) databank of quantum chemistry calculations, scientists developed a novel machine learning system for determining the miscibility of any given polymer with its solvent candidates, referred to as χ (chi) parameters.

This system has enabled scientists to overcome the limitations arising from a limited amount of experimental data on the polymer-solvent miscibility by integrating produced from the computer experiments using high-throughput quantum chemistry calculations.

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