Vibrational states of nano-confined water molecules in beryl investigated by first-principles calculations and optical experiments

2017 ◽  
Vol 19 (45) ◽  
pp. 30740-30748 ◽  
Author(s):  
M. A. Belyanchikov ◽  
E. S. Zhukova ◽  
S. Tretiak ◽  
A. Zhugayevych ◽  
M. Dressel ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
First Principles ◽  
Comprehensive Analysis ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Confined Water ◽  
Vibrational States

Using the DFT approach and optical spectroscopy, we provide a comprehensive analysis of IR excitation of water molecules confined in beryl nanopores.

scholarly journals Engineering Graphene Oxide/Water Interface from First Principles to Experiments for Electrostatic Protective Composites

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1596
Author(s):  
Luca Valentini ◽  
Silvia Bittolo Bon ◽  
Giacomo Giorgi
Keyword(s):  
Graphene Oxide ◽  
First Principles ◽  
Composite Fiber ◽  
Water Molecules ◽  
Liquid Droplets ◽  
First Principles Calculations ◽  
Voltage Output ◽  
Global Spread ◽  
Protective Fabrics ◽  
Airborne Viruses

From the global spread of COVID-19 we learned that SARS-CoV-2 virus can be transmitted via respiratory liquid droplets. In this study, we performed first-principles calculations suggesting that water molecules once in contact with the graphene oxide (GO) layer interact with its functional groups, therefore, developing an electric field induced by the heterostructure formation. Experiments on GO polymer composite film supports the theoretical findings, showing that the interaction with water aerosol generates a voltage output signal of up to −2 V. We then developed an electrostatic composite fiber by the coagulation method mixing GO with poly(methyl methacrylate) (PMMA). These findings could be used to design protective fabrics with antiviral activity against negatively charged spike proteins of airborne viruses.

scholarly journals Aquaporin-like water transport in nanoporous crystalline layered carbon nitride

2020 ◽  
Vol 6 (39) ◽  
pp. eabb6011
Author(s):  
Fabrizia Foglia ◽  
Adam J. Clancy ◽  
Jasper Berry-Gair ◽  
Karolina Lisowska ◽  
Martin C. Wilding ◽  
...  
Keyword(s):  
First Principles ◽  
High Performance ◽  
Carbon Nitride ◽  
Nanoporous Materials ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Hydrogen Bonding Interactions ◽  
Rapid Transport ◽  
Pass Through ◽  
Aquaporin Channels

Designing next-generation fuel cell and filtration devices requires the development of nanoporous materials that allow rapid and reversible uptake and directed transport of water molecules. Here, we combine neutron spectroscopy and first-principles calculations to demonstrate rapid transport of molecular H2O through nanometer-sized voids ordered within the layers of crystalline carbon nitride with a polytriazine imide structure. The transport mechanism involves a sequence of molecular orientation reversals directed by hydrogen-bonding interactions as the neutral molecules traverse the interlayer gap and pass through the intralayer voids that show similarities with the transport of water through transmembrane aquaporin channels in biological systems. The results suggest that nanoporous layered carbon nitrides can be useful for developing high-performance membranes.

Colour degradation of artworks: an ab initio approach to X-ray, electronic and optical spectroscopy analyses of vermilion photodarkening

2015 ◽  
Vol 30 (3) ◽  
pp. 588-598 ◽  
Author(s):  
C. Hogan ◽  
F. Da Pieve
Keyword(s):  
Ab Initio ◽  
Optical Spectroscopy ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray ◽  
Ab Initio Approach

First principles calculations explain the presence, colour, and photo-reactivity of Hg-containing compounds involved in vermilion degradation.

First principles calculations on oxygen vacant hydrated α-MnO2 for activating water oxidation and its self-healing mechanism

2016 ◽  
Vol 18 (32) ◽  
pp. 22196-22202 ◽  
Author(s):  
Kruthika Ganesan ◽  
P. Murugan
Keyword(s):  
Oxygen Vacancy ◽  
Water Molecule ◽  
First Principles ◽  
Water Oxidation ◽  
Proton Transport ◽  
Water Molecules ◽  
Self Healing ◽  
First Principles Calculations

In the presence of an oxygen vacancy, two water molecules in the tunnel of an α-MnO2 lattice form a dimer and dissociate into ions, which can activate water oxidation. And also self-healing can happen if at least one more water molecule is available in the tunnel for proton transport.

scholarly journals Stabilization of ammonia-rich hydrate inside icy planets

2017 ◽  
Vol 114 (34) ◽  
pp. 9003-9008 ◽  
Author(s):  
Victor Naden Robinson ◽  
Yanchao Wang ◽  
Yanming Ma ◽  
Andreas Hermann
Keyword(s):  
First Principles ◽  
High Pressures ◽  
Structural Evolution ◽  
Water Molecules ◽  
Water Mixture ◽  
Interior Structure ◽  
First Principles Calculations ◽  
Concentration Gradients ◽  
Ammonia Water ◽  
Specific Composition

The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets—as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H2O)(NH3)2, is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O2−(NH4+)2, where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia–water mixture. This suggests it precipitates out of any ammonia–water mixture at sufficiently high pressures and thus forms an important component of icy planets.

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