29,322 results match your criteria Physical chemistry chemical physics : PCCP[Journal]


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Phys Chem Chem Phys 2019 Apr 17;21(16):8600. Epub 2019 Apr 17.

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http://dx.doi.org/10.1039/C9CP90119ADOI Listing

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Phys Chem Chem Phys 2019 Apr 17;21(16):8599. Epub 2019 Apr 17.

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http://dx.doi.org/10.1039/C9CP90118CDOI Listing

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Phys Chem Chem Phys 2019 Apr 17;21(16):8185-8196. Epub 2019 Apr 17.

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http://dx.doi.org/10.1039/C9CP90117EDOI Listing

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Phys Chem Chem Phys 2019 Apr 17;21(16):8184. Epub 2019 Apr 17.

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http://dx.doi.org/10.1039/C9CP90116GDOI Listing

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Phys Chem Chem Phys 2019 Apr 17;21(16):8183. Epub 2019 Apr 17.

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http://dx.doi.org/10.1039/C9CP90115ADOI Listing

Role of the carbon source in the transformation of amorphous carbon to graphene during rapid thermal processing.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Computational Science Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.

A fast transfer-free synthesis of a graphene structure can be successfully achieved by Ni-catalysed transformation of amorphous carbon (a-C) during rapid thermal processing, but the role of the a-C structure in the a-C-to-graphene transformation is still unclear. In this paper, the dependence of the transformation of a-C to graphene, the diffusion behaviour of C, and the graphene quality on the a-C structures was comparatively investigated by reactive molecular dynamics simulation and Ni was selected as a catalyst. The results demonstrated that different a-C structures affected the diffusion of C into Ni layers and the re-dissolving behaviour of the grown graphitic structures, and thus dominated the remnant number of C atoms, which played a critical role in the formation and quality of graphene. Read More

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http://dx.doi.org/10.1039/c9cp01305aDOI Listing

Computer simulations of the adsorption of an N-terminal peptide of statherin, SN15, and its mutants on hydroxyapatite surfaces.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Guangdong Provincial Key Lab for Green Chemical Product Technology, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510640, People's Republic of China.

Statherin is a 43 amino acid long protein, which plays an important role in the process of biomineralization of enamel. In this work, we investigated the solvent effect on the adsorption of a peptide from the N-terminus of statherin, SN15, and its mutants SNA15 and SNS15 on the (001) face of hydroxyapatite [Ca10(PO4)6(OH)2, or HAP] with molecular dynamics simulations. The simulation results showed that the adsorption of the three peptides onto the HAP(001) surface was primarily driven by salt-bridge and electrostatic attraction in calcium phosphate (Ca/P) and sodium chloride (NaCl) solutions, respectively. Read More

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http://dx.doi.org/10.1039/c9cp01638dDOI Listing

Chlorine-assisted fabrication of hybrid supramolecular structures via electrostatic interactions.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Interdisciplinary Materials Research Center, College of Materials Science and Engineering, Tongji University, Shanghai 201804, P. R. China.

Supramolecular self-assembly is a spontaneous process relying on non-covalent intermolecular interactions. Among them, electrostatic interactions generated by organic molecules interacting with alkali metals and/or halogens play an important role in structural formation. Herein, we choose cytosine and NaCl as a model system and, from the interplay of STM imaging and DFT calculations, a hybrid network composed of both metal-organic and pure organic motifs interlinked by Cl ions via electrostatic interactions is observed on the Au(111) surface. Read More

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http://xlink.rsc.org/?DOI=C9CP01046G
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http://dx.doi.org/10.1039/c9cp01046gDOI Listing
April 2019
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Structure and proton conduction in sulfonated poly(ether ether ketone) semi-permeable membranes: a multi-scale computational approach.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Departamento de Materiales y Nanotecnología, Universidad Nacional de Colombia - Medellín, Medellín, Colombia and Colombia/Wisconsin One-Health Consortium, Universidad Nacional de Colombia - Medellín, Medellín, Colombia.

The design of polymeric membranes for proton or ionic exchange highly depends on the fundamental understanding of the physical and molecular mechanisms that control the formation of the conduction channels. There is an inherent relation between the dynamical structure of the polymeric membrane and the electrostatic forces that drive membrane segregation and proton transport. Here, we used a multi-scale computational approach to analyze the morphology of sulfonated poly(ether ether ketone) membranes at the mesoscale. Read More

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http://dx.doi.org/10.1039/c9cp00598fDOI Listing

Which types of clay minerals fix cesium ions effectively? the "cavity-charge matching effect".

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan.

How can radioactive Cs+ ions be removed from aqueous solution? From this perspective, the adsorption of Cs+ was investigated by using five types of clay minerals possessing different charge exchange capacities. The fixation ability for Cs+ depended on the charge exchange capacity of the clay minerals. Phlogopite and vermiculite, where the number of charges is almost equal to half the number of siloxane ditrigonal cavities in the structure, exhibited a strong Cs+ fixation ability among these clay minerals. Read More

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http://dx.doi.org/10.1039/c9cp00457bDOI Listing

The impact of carbonate solvents on the self-discharge, thermal stability and performance retention of high voltage electrochemical double layer capacitors.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Institute for Technical and Environmental Chemistry (ITUC), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena, Germany. and Center for Energy and Environmental Chemistry Jena (CEEC Jena), Philosophenweg 7a, 07743 Jena, Germany.

Advanced electrolytes for supercapacitors with high electrochemical stability are necessary to improve the suitability of supercapacitors for many applications. In this work we investigated electrolytes based on the solvent propylene carbonate (PC) and butylene carbonate (BC). A comparison of different solvent-salt combinations shows that 1 M N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) in BC is superior to conventionally used PC-based electrolytes examined in this work in terms of voltage window and capacitance. Read More

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http://dx.doi.org/10.1039/c9cp00483aDOI Listing

Mechanistic study of the reaction of CHF with Cl atoms in the absence and presence of CH or CH: decomposition of CHFOH and fate of the CHFO radical.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Chemical Engineering, University of Melbourne, Victoria 3010, Australia.

To assess the atmospheric fate of fluorinated compounds, chamber experiments were performed with Fourier transform infrared spectroscopy investigating the products of difluoromethane, CH2F2, at 296 ± 2 K. The reactions were initiated by reaction of CH2F2 with Cl atoms in the absence and presence of CH4 or C2H6 in air or O2. No evidence of formation of the fluorinated alcohol, CHF2OH, from the reactions of the CHF2O2 radical with either CH3O2 or CH3CH2O2 was observed. Read More

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http://dx.doi.org/10.1039/c8cp06425cDOI Listing

Silicene-supported TiO nanostructures: a theoretical study of electronic and optical properties.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Physics, Michigan Technological University, Houghton, MI 49931, USA.

Titania (TiO2) is a material of choice for energy-related applications, such as photovoltaics and photocatalysis. The presence of a large band gap and fast electron-hole recombination occurring in the lattice significantly reduce the material's quantum efficiency, and therefore limit industrial-scale applications. In this article, we investigate whether silicene can be a viable substrate for TiO2 nanostructures in photocatalytic applications. Read More

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http://dx.doi.org/10.1039/c9cp00894bDOI Listing

COSMOplex: self-consistent simulation of self-organizing inhomogeneous systems based on COSMO-RS.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

COSMOlogic GmbH & Co KG, Imbacher Weg 46, D-51379 Leverkusen, Germany. and School of Chemistry and Chemical Engineering, Nanjing University, China.

During the past 20 years, the efficient combination of quantum chemical calculations with statistical thermodynamics by the COSMO-RS method has become an important alternative to force-field based simulations for the accurate prediction of free energies of molecules in liquid systems. While it was originally restricted to homogeneous liquids, it later has been extended to the prediction of the free energy of molecules in inhomogeneous systems such as micelles, biomembranes, or liquid interfaces, but these calculations were based on external input about the structure of the inhomogeneous system. Here we report the rigorous extension of COSMO-RS to a self-consistent prediction of the structure and the free energies of molecules in self-organizing inhomogeneous systems. Read More

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http://dx.doi.org/10.1039/c9cp01169bDOI Listing

Microscopic origin of the scattering pre-peak in aqueous propylamine mixtures: X-ray and neutron experiments versus simulations.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Sorbonne Université, Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), 4 Place Jussieu, F75252, Paris cedex 05, France.

The structure of aqueous propylamine mixtures is investigated through X-ray and neutron scattering experiments, and the scattered intensities compared with computer simulation data. Both sets of data show a prominent scattering pre-peak, which first appears at propylamine mole fraction x ≥ 0.1 around scattering vector k ≈ 0. Read More

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http://dx.doi.org/10.1039/c9cp01137dDOI Listing

The effect of co-adsorbed solvent molecules on H binding to metal alkoxides.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA.

The introduction of metal alkoxides has been proposed as an attractive option to enhance hydrogen binding energies in porous materials such as metal-organic frameworks (MOFs) for room-temperature hydrogen storage applications. The presence of residual solvent molecules from MOF synthesis can, however, affect the performance of these functional groups. We perform quantum chemical calculations to predict solvent binding energies onto the metal-alkoxides and the temperatures required to drive off the solvent molecules and successfully activate porous materials with these moieties. Read More

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http://xlink.rsc.org/?DOI=C9CP00754G
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http://dx.doi.org/10.1039/c9cp00754gDOI Listing
April 2019
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Theoretical analysis of glyoxal condensation with ammonia in aqueous solution.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

National Research Tomsk State University, 36, Lenin Avenue, Tomsk, 634050, Russia.

The reactions of glyoxal with ammonia, ammonium salts, and amines cause the formation of the secondary organic aerosol (SOA) components (imidazole and its derivatives) in the atmosphere. The interaction of glyoxal and ammonia in aqueous solution is a primary reaction for these processes, and the explanation of its mechanism will allow developing the methods to control the formation of the SOA components. A detailed mechanism for the formation of key intermediates, namely, ethanediimine, diaminoethanediol, and aminoethanetriol, required for the imidazole ring cyclization, is proposed, and its potential energy surface (PES) has been constructed. Read More

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http://xlink.rsc.org/?DOI=C8CP07270A
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http://dx.doi.org/10.1039/c8cp07270aDOI Listing
April 2019
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Topological Dirac states in transition-metal monolayers on graphyne.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.

Realizing topological Dirac states in two-dimensional (2D) magnetic materials is particularly important to spintronics. Here, we propose that such states can be obtained in a transition-metal (Hf) monolayer grown on a 2D substrate with hexagonal hollow geometry (graphyne). We find that the significant orbital hybridizations between Hf and C atoms can induce sizable magnetism and bring three Dirac cones at/around each high-symmetry K(K') point in the Brillouin zone. Read More

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http://dx.doi.org/10.1039/c9cp01153fDOI Listing

Photoionization studies of reactive intermediates using synchrotron radiation.

Authors:
John M Dyke

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

School of Chemistry, University of Southampton, SO17 1BJ, UK.

Photoionization of reactive intermediates with synchrotron radiation has reached a sufficiently advanced stage of development that it can now contribute to a number of areas in gas-phase chemistry and physics. These include the detection and spectroscopic study of reactive intermediates produced by bimolecular reactions, photolysis, pyrolysis or discharge sources, and the monitoring of reactive intermediates in situ in environments such as flames. This review summarises advances in the study of reactive intermediates with synchrotron radiation using photoelectron spectroscopy (PES) and constant-ionic-state (CIS) methods with angular resolution, and threshold photoelectron spectroscopy (TPES), taking examples mainly from the recent work of the Southampton group. Read More

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http://dx.doi.org/10.1039/c9cp00623kDOI Listing

The multiple dissociation constants of glutathione disulfide: interpreting experimental pH-titration curves with ab initio MD simulations.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Inorganic and Physical Chemistry, IISc, Bangalore, India.

The hexapeptide glutathione disulfide (GSSG) has six ionizable groups with six associated dissociation constants. The experimentally measured pH-titration curve, however, does not exhibit the six corresponding equivalence points and bears little resemblance to standard textbook examples of acid-base pH-titration curves. The curve highlights the difficulties in determining multiple pKa values of polyprotic acids - typically proteins and peptides - from experiment. Read More

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http://dx.doi.org/10.1039/c9cp00761jDOI Listing

Enhancing high harmonic generation by the global optimization of a two-color chirped laser field.

Phys Chem Chem Phys 2019 Apr 17. Epub 2019 Apr 17.

Department of Physics, Sharif University of Technology, P.O. Box 11365-9567, Tehran, Iran.

Enhanced high harmonics are generated by local and global optimization approaches to achieve a supercontinuum spectrum. Based on time-dependent density functional theory calculations, the optimum convolution of a two-color chirped pulse from an N2O molecule implements a significant enhancement of cutoff frequency and high harmonic yield. The optimization is done by controlling the effective chirp parameters and the carrier-envelope phase of the designed laser field. Read More

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http://dx.doi.org/10.1039/c8cp07619gDOI Listing

How water flips at charged titanium dioxide: an SFG-study on the water-TiO interface.

Phys Chem Chem Phys 2019 Apr 16. Epub 2019 Apr 16.

Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. and Department of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria.

Photocatalytic splitting of water into hydrogen and oxygen by utilizing sunlight and a photocatalyst is a promising way of generating clean energy. Here, we report a molecular-level study on heavy water (D2O) interacting with TiO2 as a model photocatalyst. We employed the surface specific technique Sum-Frequency-Generation (SFG) spectroscopy to determine the nature of the hydrogen bonding environment and the orientation of interfacial water molecules using their OD-stretch vibrations as reporters. Read More

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http://xlink.rsc.org/?DOI=C9CP01131E
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http://dx.doi.org/10.1039/c9cp01131eDOI Listing
April 2019
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Reaction mechanism between small-sized Ce clusters and water molecules II: an ab initio investigation on Ce (n = 1-3) + mHO (m = 2-6).

Phys Chem Chem Phys 2019 Apr 16. Epub 2019 Apr 16.

Department of Chemistry and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.

Possible reactions between the products of the three independent reactions involving a small Ce cluster and a single water molecule, Cen + H2O (n = 1-3), and an additional H2O molecule are systematically investigated. The ground-state isomers of the final products and the reaction pathways involving multiple water molecules are predicted. We find that under either ambient or UV-irradiation conditions, all the reactions can entail low energy barriers. Read More

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http://dx.doi.org/10.1039/c9cp01027kDOI Listing

Electrochemical reduction of CO using palladium modified boron-doped diamond electrodes: enhancing the production of CO.

Phys Chem Chem Phys 2019 Apr 16. Epub 2019 Apr 16.

Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522, Japan. and ACCEL, Japan Science and Technology Agency, 5-3 Yonbancho, Chiyoda 102-8666, Japan.

In recent years, boron-doped diamond (BDD) has been utilized as an electrode for the electrochemical reduction of CO2, and several reports have been published on this. The wide potential window of BDD enables the hydrogen evolution reaction, which competes with CO2 reduction, to be suppressed. On the other hand, the high overpotential is still a problem. Read More

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http://dx.doi.org/10.1039/c9cp01409hDOI Listing

Energy conversion efficiency in low- and atmospheric-pressure plasma polymerization processes with hydrocarbons.

Phys Chem Chem Phys 2019 Apr 16. Epub 2019 Apr 16.

Department of Engineering Physics and Groupe des Couches Minces (GCM), Polytechnique Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7, Canada.

Since the earliest days of this field there has been an interest in correlating the structure of plasma polymer (PP) coatings with deposition parameters, most particularly with energy input per monomer molecule, Em. Both of our laboratories have developed methods for measuring Em (or somewhat equivalent, the apparent activation energy, Ea) in low- (LP) and atmospheric-pressure (AP) electrical discharge plasmas. We recently proposed a new parameter, energy conversion efficiency (ECE), which for the first time permits direct comparison of LP and AP experiments. Read More

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http://dx.doi.org/10.1039/c9cp01567aDOI Listing
April 2019
1 Read

Photoinduced anisotropic distortion as the electron trapping site of tungsten trioxide by ultrafast W L-edge X-ray absorption spectroscopy with full potential multiple scattering calculations.

Phys Chem Chem Phys 2019 Apr 16. Epub 2019 Apr 16.

Institute for Catalysis Hokkaido University, Sapporo 001-0021, Japan.

Understanding the excited state of photocatalysts is significant to improve their activity for water splitting reaction. X-ray absorption fine structure (XAFS) spectroscopy in X-ray free electron lasers (XFEL) is a powerful method to address dynamic changes in electronic states and structures of photocatalysts in the excited state in ultrafast short time scales. The ultrafast atomic-scale local structural change in photoexcited WO3 was observed by W L1 edge XAFS spectroscopy using an XFEL. Read More

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http://dx.doi.org/10.1039/c9cp01332fDOI Listing

Two solvent-induced variable host-guest two-dimensional binary frameworks mediated by hydrogen bonding.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Department of Science, Nanchang Institute of Technology, Nanchang 330099, P. R. China.

Two-dimensional binary hydrogen-bonded organic frameworks constructed from 1,3,5-benzenetricarboxylic acid (TMA) and 4,4'-biphenyldicarboxylic acid (BDA) on highly oriented pyrolytic graphite (HOPG) were investigated by scanning tunneling microscopy (STM) in heptanoic acid and octanoic acid solvents. High-resolution STM observations demonstrated that various assemblies of hydrogen-bonded networks are strongly dependent on the nature of the solvent. Well-ordered porous rectangular flowerlike networks were revealed at the heptanoic acid/HOPG interface, whereas two different coexisting densely packed guest-host BDA/TMA structures were observed at the octanoic acid/HOPG interface. Read More

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http://dx.doi.org/10.1039/c9cp01395dDOI Listing

The scandium doped boron cluster BSc: a fruit can-like structure.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Institute for Computational Science and Technology (ICST), Ho Chi Minh City, Vietnam. and Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium.

A systematic exploration of the potential energy surface through evolutionary search algorithms was carried out to identify the most stable B27Sc2+ structure. A nearly perfect boron box was found featuring a triple ring tubular shape with high D9h symmetry formed by three B9 strings connected with each other and the box is capped by an Sc-Sc dimer. Each Sc atom is placed at the centre of a B9 terminal string along the C9 axis. Read More

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http://xlink.rsc.org/?DOI=C9CP00892F
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http://dx.doi.org/10.1039/c9cp00892fDOI Listing
April 2019
2 Reads

Oscillations of pH in the urea-urease system in a membrane reactor.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Department of Chemical Engineering, University of Chemistry and Technology, Prague, Technická 5, 166 28 Praha 6, Czech Republic.

Herein, we present direct experimental evidence of pH oscillatory dynamics in the urea-urease enzymatic reaction conducted in a continuous reactor-membrane-reservoir system. Our results are consistent with earlier model predictions requiring differential transport of H+ and substrate. We report oscillations with periods in hundreds of seconds and the amplitude of ∼0. Read More

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http://dx.doi.org/10.1039/c9cp00630cDOI Listing

Notable effect of water on excess electron attachment to aqueous DNA deoxyribonucleosides.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023, China.

Computations using the combined quantum mechanical/molecular mechanical (QM/MM) method were performed to investigate excess electron attachment to and detachment from aqueous deoxyribonucleosides (dRNs). The QM/MM vertical electron affinities (VEAs) of four dRNs are higher than the values of the corresponding nucleobases by ∼0.20 eV. Read More

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http://xlink.rsc.org/?DOI=C9CP00536F
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http://dx.doi.org/10.1039/c9cp00536fDOI Listing
April 2019
1 Read

Physical origin underlying the prenucleation-cluster-mediated nonclassical nucleation pathways for calcium phosphate.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, China.

The involvement of prenucleation clusters (PNCs) in crystallization from a supersaturated solution has been recently admitted within the framework of nonclassical nucleation theory; however, little is known about PNCs, at the quantitative level, for their formation mechanism and stability, the new phase formed by them, as well as their impact on nucleation barriers. Herein, using the sophisticated free energy calculations with a cumulative simulation time of over 5 μs, we identify a thermodynamically favored pathway of the PNC-mediated nucleation for calcium phosphate, starting with the ion pair association in solution. We demonstrate that such an ion association occurs not only between cations and anions, but also for the polyatomic species with charges of the same sign, which, in fact, leads to PNC formation via the consecutive coordination of the phosphate ions to calcium. Read More

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http://dx.doi.org/10.1039/c9cp00919aDOI Listing

A generalized van der Waals model for light gas adsorption prediction in IRMOFs.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82071-3295, USA.

By making reasonable simplifications to the structures of isoreticular metal-organic frameworks (IRMOFs) and defining important attractive regions of square-well potential, an adsorption model derived from the generalized van der Waals partition function is proposed to describe the isotherms of light gas adsorption in IRMOFs. The simplification of the structures is based on the geometries of the accessible surfaces and the dimensions of the frameworks, and the locations of the attractive regions are defined by examining the distribution of the adsorbate molecules. Grand Canonical Monte Carlo (GCMC) simulations using the simplified structures with square-well potentials and the complete atomic structures with Lennard-Jones and coulombic potentials are performed and compared to verify the reliability of the simplification. Read More

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http://dx.doi.org/10.1039/c9cp00285eDOI Listing
April 2019
1 Read

The mechanism and rate constants for oxidation of indenyl radical CH with molecular oxygen O: a theoretical study.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Samara University, Samara, 443086, Russia. and Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.

Ab initio G3(MP2,CC)//B3LYP/6-311G(d,p) calculations have been carried out to map out the C9H7O2 potential energy surface in relation to the reaction of the 1-indenyl radical with molecular oxygen. The resulting energetics and molecular parameters of the species involved in the reaction have been then utilized in Rice-Ramsperger-Kassel-Marcus master equation calculations of temperature- and pressure-dependent reaction rate constants and product branching ratios. The results demonstrate that, while the reaction is insignificant at low temperatures, at higher temperatures, above 800 K or higher depending on the pressure, the prevailing reaction channel leads to the formation of the 1-H-inden-1-one + OH products via a 1,3-H shift from C to O in the initial association complex W1 accompanied by OH elimination through a high barrier of 25. Read More

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http://dx.doi.org/10.1039/c9cp01122fDOI Listing

Structural analysis of the initial lithiation of NiO thin film electrodes.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA. and Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.

Observations of the initial lithiation of NiO electrodes demonstrate how to seed conversion reactions using interfaces in a thin film Ni/NiO bilayer architecture. Operando X-ray reflectivity (XRR) reveals that structural changes in a NiO film begin at potentials near the theoretical reduction potential (1.8-2. Read More

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http://xlink.rsc.org/?DOI=C9CP01527B
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http://dx.doi.org/10.1039/c9cp01527bDOI Listing
April 2019
1 Read

Fluorescence measurements of peroxynitrite/peroxynitrous acid in cold air plasma treated aqueous solutions.

Phys Chem Chem Phys 2019 Apr 15. Epub 2019 Apr 15.

Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava, Slovakia.

Qualitative detection of peroxynitrite/peroxynitrous acid (ONOO-/ONOOH) as one of the key bactericidal agents produced in cold air plasma activated aqueous solutions is presented. We examined the use of the 2,7-dichlorodihydrofluorescein diacetate (H2DCFDA) fluorescent dye to detect ONOO-/ONOOH in plasma activated non-buffered water (PAW) or buffered solution (PAPB) generated by DC-driven self-pulsed transient spark discharge at atmospheric pressure in ambient air. The diagnostic selectivity of H2DCFDA to reactive oxygen and nitrogen species (RONS) typical of plasma activated aqueous solutions was examined by using various scavengers of RONS. Read More

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http://dx.doi.org/10.1039/c9cp00871cDOI Listing

Theoretical insights into the formation and stability of radical oxygen species in cryptochromes.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

Aix Marseille Univ, CNRS, ICR, Marseille, France.

Cryptochrome is a blue-light absorbing flavoprotein containing a flavin adenine dinucleotide (FAD) cofactor. FAD can accept up to two electrons and two protons, which can be subsequently transferred to substrates present in the binding pocket. It is well known that reactive oxygen species are generated when triplet molecular oxygen is present in the cavity. Read More

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http://dx.doi.org/10.1039/c9cp00782bDOI Listing

Using hydrogenated and perfluorinated gases to probe the interactions and structure of fluorinated ionic liquids.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

Laboratoire de Chimie de l'ENS de Lyon, CNRS & ENS de Lyon, Lyon, France.

After studying the properties of a mixture of hydrogenated and fluorinated ionic liquids we have measured the solubility of perfluoromethane, perfluoroethane and perfluoropropane in 1-alkyl-3-methylimidazolium based ionic liquids with hydrogenated or fluorinated alkyl side-chains: 1-octyl-3-methylimidazolium bis[trifluoromethylsulfonyl]amide ([C8C1Im][NTf2]), 1-octyl-3-methylimidazolium bis[pentafluoroethylsulfonyl]amide ([C8C1Im][BETI]), 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium bis[trifluoromethylsulfonyl]amide ([C8H4F13C1Im][NTf2]), and 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium bis[pentafluoroethylsulfonyl]amide ([C8H4F13C1Im][BETI]). The ionic liquids expand on mixing and mix endothermally with a relatively high enthalpy of mixing (ΔmixH for [C8C1Im]x[C8H4F13C1Im](1-x)[NTf2] of ca. 0. Read More

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http://xlink.rsc.org/?DOI=C9CP00593E
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http://dx.doi.org/10.1039/c9cp00593eDOI Listing
April 2019
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Dissociative electron attachment to HNO and its hydrates: energy-selective electron-induced chemistry.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

J. Heyrovský Institute of Physical Chemistry, v.v.i., Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.

We probe the negative ion production upon the interaction of free electrons with gas-phase HNO3 and its mixed clusters with water. The electron-induced chemistry changes strongly with clustering, exhibiting significant electron energy dependence. For HNO3 hydrates, we identified three involved energy ranges with different behavior: low energies up to about 3. Read More

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http://dx.doi.org/10.1039/c9cp00990fDOI Listing

Vibronic interaction in CO photo-detachment: Jahn-Teller effects beyond structural distortion and general formalisms for vibronic Hamiltonians in trigonal symmetries.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada.

Recently, the negative ion photoelectron spectrum of CO3- was reported and the second lowest energy band is assigned to the close-lying 3E'' and 3E' states that undergo Jahn-Teller distortions (Chem. Sci., 2016, 7, 1142). Read More

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http://dx.doi.org/10.1039/c9cp01352kDOI Listing

A rational design of manganese electrocatalysts for Lewis acid-assisted carbon dioxide reduction.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan, 250014, P. R. China.

Herein, the mechanisms of Brønsted acid- and Lewis acid-assisted CO2 electroreduction by Mn(mesbpy)(CO)3Br (1) were investigated by density functional theory calculations. Our results indicate that for the Lewis acid-assisted cycle, an energy sink (13) is present owing to the interaction between Mg(OTf)2 and activated CO2, which is disadvantageous to the apparent activation energy (ΔG≠). Moreover, a series of substituted 13 counterparts were investigated to reduce the energy sink and decrease ΔG≠. Read More

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http://dx.doi.org/10.1039/c9cp00514eDOI Listing

Electronic and magnetic properties of the one-dimensional interfaces of two-dimensional lateral GeC/BP heterostructures.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.

We studied the electronic and magnetic properties of one-dimensional (1D) interfaces of two dimensional (2D) GeC/BP lateral heterostructures by first-principles calculations. We showed that an inner electric field exists in the heterostructures, and the 1D interfaces exhibit metallic properties when the ribbon width is larger than a critical value. In other words, the 1DEG/1DHG (one dimensional electron gas/one dimensional hole gas) with π bonding character appear at the interfaces. Read More

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http://dx.doi.org/10.1039/c9cp01196jDOI Listing

Identification of ion pairs in solution by IR spectroscopy: crucial contributions of gas phase data and simulations.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

LIDYL, CEA, CNRS, Université Paris Saclay, CEA Saclay, Bât 522, 91191 Gif-sur-Yvette, France.

In a context where structure elucidation of ion pairs in solution remains a contemporary challenge, this work explores an original approach where accurate gas phase spectroscopic data are used to refine high level quantum chemistry calculations of ion pairs in solution, resulting in an unprecedented level of accuracy in vibrational frequency prediction. First, gas phase studies focus on a series of isolated contact ion pairs (M+, Ph-CH2-COO-, with M = Li, Na, K, Rb, Cs) for which conformer-selective IR spectra in the CO2- stretch region are recorded. These experiments reveal the interactions at play in isolated contact ion pairs, and provide vibrational frequencies enabling us to assess the accuracy of the theoretical approach used, i. Read More

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http://dx.doi.org/10.1039/c9cp00700hDOI Listing

Imaging inelastic scattering of CO with argon: polarization dependent differential cross sections.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

Department of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.

Rotationally inelastic scattering of carbon monoxide (CO) with Argon at a collision energy of 700 cm-1 has been investigated by measuring polarization dependent differential scattering cross sections (PDDCSs) for rotationally excited CO molecules using a crossed molecular beam apparatus coupled with velocity-map ion imaging. A simple and robust (1 + 1' + 1'') VUV (Vacuum Ultra-Violet) REMPI (Resonance Enhanced Multi Photon Ionization) scheme is used and images are obtained by setting the VUV light polarization direction parallel or perpendicular to the scattering plane. Clear differences between the images for the two polarizations are observed, indicating strong collision induced alignment of the rotational angular momentum of scattered CO. Read More

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http://dx.doi.org/10.1039/c9cp00876dDOI Listing

Electric field control of resistive switching and magnetization in epitaxial LaBaCoO thin films.

Phys Chem Chem Phys 2019 Apr 12. Epub 2019 Apr 12.

Key Laboratory of Material Processing and Die & Mould Technology, Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.

The low operating temperature and volatile characteristics of the magnetization change are the main obstacles for the practical applications of spintronic and magnetic memories. In this work, both the resistive switching and magnetization switching are realized in Pt/LaBaCo2O5+δ (LBCO)/Nb-doped SrTiO3 (Nb-STO) devices at room temperature through an electric field. Unlike the traditional approach of an external stress inducing a volatile magnetization change, the magnetization in the Pt/LBCO/Nb-STO device is modulated by an electrical field, along with the resistive switching. Read More

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http://xlink.rsc.org/?DOI=C9CP00596J
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http://dx.doi.org/10.1039/c9cp00596jDOI Listing
April 2019
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Effects of temperature and pressure on the optical and vibrational properties of thermoelectric SnSe.

Phys Chem Chem Phys 2019 Apr 11. Epub 2019 Apr 11.

Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.

We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes. Our high-temperature investigations at ambient pressure have successfully reproduced the progressive enhancement of the free carrier concentration upon approaching the Pnma → Bbmm transition, whereas the pressure-induced Pnma → Bbmm transformation at ambient temperature, accompanied by an electronic semiconductor → semi-metal transition, has been identified for bulk SnSe close to 10 GPa. Modeling of the Raman-active vibrations revealed that three-phonon anharmonic processes dominate the temperature-induced mode frequency evolution. Read More

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http://dx.doi.org/10.1039/c9cp00897gDOI Listing

Destructive role of oxygen in growth of molybdenum disulfide determined by secondary ion mass spectrometry.

Phys Chem Chem Phys 2019 Apr 11. Epub 2019 Apr 11.

Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw, Poland.

The application of secondary ion mass spectrometry (SIMS) in investigation and comparison of molybdenum disulfide (MoS2) films grown on SiO2, Al2O3 and BN substrates is presented. SIMS measurements of the MoS2/substrate interface reveals oxygen out-diffusion from the substrates containing oxygen and the formation of an amorphous MoOS layer in addition to MoS2. The total area of MoS2 domains covering the substrate is directly related to the type of substrate. Read More

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http://dx.doi.org/10.1039/c9cp00613cDOI Listing

Si 1s, 2s and 2p lifetime broadening of SiX (X = F, Cl, Br, CH) molecules: SiF anomalous behaviour reassessed.

Phys Chem Chem Phys 2019 Apr 11. Epub 2019 Apr 11.

Sorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, LCPMR, F-75005 Paris Cedex 05, France and Synchrotron SOLEIL, l'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France.

The Si 1s-1, Si 2s-1, and Si 2p-1 photoelectron spectra of the SiX4 molecules with X = F, Cl, Br, CH3 were measured. From these spectra the Si 1s-1 and Si 2s-1 lifetime broadenings were determined, revealing a significantly larger value for the Si 2s-1 core hole of SiF4 than for the same core hole of the other molecules of the sequence. This finding is in line with the results of the Si 2p-1 core holes of a number of SiX4 molecules, with an exceptionally large broadening for SiF4. Read More

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http://dx.doi.org/10.1039/c8cp07369dDOI Listing

Relationship between ferromagnetism and formation of complex carbon bonds in carbon doped ZnO powders.

Phys Chem Chem Phys 2019 Apr 10. Epub 2019 Apr 10.

Department of Physics, Boise State University, Boise, Idaho 83725-1570, USA.

We have investigated the possible relationship between defects, carbon bonds and the associated magnetic properties of carbon doped ZnO powders with intentional nominal carbon concentrations of 0, 1, 3, 5, 8 and 10 mol%. The samples were prepared by mechanical milling assisted by solid state reaction and carefully characterized using different techniques. X-ray diffraction and micro-Raman analysis revealed structural changes below and above the nominal carbon doping concentration of 3 mol% along with formation of intrinsic defect complexes. Read More

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http://xlink.rsc.org/?DOI=C9CP01277J
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http://dx.doi.org/10.1039/c9cp01277jDOI Listing
April 2019
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What are the effects of the serine triad on proton conduction of an influenza B M2 channel? An investigation by molecular dynamics simulations.

Phys Chem Chem Phys 2019 Apr 10. Epub 2019 Apr 10.

Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Jilin University, Changchun 130023, People's Republic of China. and Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130023, People's Republic of China.

The tetrameric influenza B M2 channel (BM2), an acid activated proton channel, is important in the influenza virus B lifecycle. A conserved HxxxW motif is responsible for proton conduction and channel gating. In this study, to explore the effects of the serine triad (S9, S12 and S16) on proton conduction, we performed classical molecular dynamics (CMD) simulations and adaptive steered molecular dynamics (ASMD) simulations at different protonation states of the H19 tetrad. Read More

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http://xlink.rsc.org/?DOI=C9CP00612E
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http://dx.doi.org/10.1039/c9cp00612eDOI Listing
April 2019
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Unraveling the molecular mechanisms of color expression in anthocyanins.

Phys Chem Chem Phys 2019 Apr 10. Epub 2019 Apr 10.

SISSA - Scuola Internazionale Superiore di Studi Avanzati, via Bonomea 265, 34125 Trieste, Italy. and CNR-IOM DEMOCRITOS, SISSA, Trieste, Italy.

Anthocyanins are a broad family of natural dyes, increasingly finding application as substitutes for artificial colorants in the food industry. In spite of their importance and ubiquity, the molecular principles responsible for their extreme color variability are poorly known. We address these mechanisms by computer simulations and photoabsorption experiments of cyanidin-3-O-glucoside in water solution, as a proxy for more complex members of the family. Read More

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http://dx.doi.org/10.1039/c9cp00747dDOI Listing