jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Chaoran Dong | Cheng Lin | Panjie Li | Jong Hyeok Park | Jinyou Shen | Kan Zhang
Source: Angewandte Chemie (article, 2024-12-31)
Field: Materials Science — Materials Chemistry

Surface Coverage Tuning for Suppressing Over‐Oxidation: A Case of Photoelectrochemical Alcohol‐to‐Aldehyde/Ketone Conversion Abstract Suppressing over‐oxidation is a crucial challenge for various chemical intermediate synthesis in heterogeneous catalysis. The distribution of oxidative species and the substrate coverage, governed by the direction of electron transfer, are believed to influence the oxidation extent. In this study, we presented an experimental realization of surface coverage modulation on a photoelectrode using a photo‐induced charge activation method. Through the surface coverage modulation, both pre‐oxidized alcohol substrates and surface coverage were increased, which not only improved the reaction kinetics but also suppressed the over‐oxidation of the generated aldehydes/ketones. As a demonstration, the Faradaic efficiency for the conversion of glycerol to dihydroxyacetone increased from 31.8 % to 46.8 % (with selectivity rising from 47.6 % to 71.3 %), from 73.4 % to 87.8 % for benzyl alcohol to benzyl aldehyde (selectivity increasing from 76.7 % to 92.4 %) and from 4.2 % to 53.6 % for ethylene glycol to glycolaldehyde (selectivity increasing from 6.2 % to 62.7 %). Our findings offer a promising strategy for the production of high‐value carbon products in heterogeneous catalysis. Glycolaldehyde ; Aldehyde ; Selectivity ; Chemistry ; Ethylene glycol ; Ketone ; Catalysis ; Alcohol oxidation ; Photochemistry ; Substrate (aquarium) ; Alcohol ; Benzyl alcohol ; Faraday efficiency ; Electrocatalyst ; Electrochemistry ; Organic chemistry ; Electrode Catalytic Processes in Materials Science ; CO2 Reduction Techniques and Catalysts ; Mesoporous Materials and Catalysis
Authors: Guillaume Le Breton | Bonhomme Oriane | Benichou Emmanuel | Claire Loison
Source: ChemRxiv (preprint, 2024-03-28)
Field: Chemistry — Spectroscopy

FROG : exploiting all-atom Molecular Dynamics trajectories to calculate linear and non-linear optical responses of molecular liquids within Dalton’s QM/MM polarizable embedding scheme Quantum mechanical/molecular mechanics (QM/MM) methods are interesting to model the impact of a complex environment on the spectroscopic properties of a molecule. In this context, FROG code is a tool to exploit molecular dynamics trajectories to perform QM/MM calculations of molecular optical properties. FROG stands for 'FROm molecular dynamics to second harmonic Generation' since it was developed for the calculations of hyperpolarizabilities. These are relevant to model non-linear optical intensities, and compare them with those obtained from second harmonic scattering or second harmonic generation experiments. FROG's specificity is that it is designed to study simple molecular liquids, including solvents or mixtures, from the bulk to the surface. For the QM/MM calculations, FROG relies on the Dalton package: its electronic-structure models, response theory and polarizable embedding (PE) schemes. FROG helps with the global workflow needed to deal with numerous QM/MM calculations: it permits the user to separate the system into QM and MM fragments, to write \Dalton’s inputs, to manage the submission of QM/MM calculations, to check whether \Dalton’s calculation finished successfully, and finally to perform averages on relevant QM observables. All molecules within the simulation box and several time steps are tackled within the same workflow. The platform is written in Python and installed as a package. Intermediate data such as local electric fields or individual molecular properties are accessible to the users in the form of Python object arrays. The resulting data are easily extracted, analyzed, and visualized using Python scripts that are provided in tutorials. Polarizability ; Molecular dynamics ; Embedding ; Atom (system on chip) ; Scheme (mathematics) ; Statistical physics ; Physics ; Computational chemistry ; Quantum mechanics ; Chemistry ; Computer science ; Mathematics ; Molecule ; Mathematical analysis ; Artificial intelligence Spectroscopy and Laser Applications ; Spectroscopy and Quantum Chemical Studies ; Electron Spin Resonance Studies
Authors: Niloofar Ebrahimzadeh Esfahani | Jaroslav Kováč | Giuseppe Maruccio | Silvia Rizzato | Soňa Kováčová
Source: Preprints.org (preprint, 2024-03-26)
Field: Materials Science — Surfaces, Coatings and Films

Comparative Simulation of Plasmonic Nanostructures: Optical Response of Periodic Metal Nanostrip and Nanodisk Arrays on Mirror In this work, two plasmonic structures with two different periodic nanostructures (nanodisk and nanostrip arrays) separated from the gold layer by an ultrathin dielectric Al2O3 layer are proposed, and their optical properties are simulated as 3-dimensional models using COMSOL Multiphysics software tool. The optical responses, such as the amplification of the electric field and the scattering, absorption and extinction cross sections of the two structures, are investigated and compared. The results show that both structures show strong field enhancement in their gap layer, and the structure with the periodic array of metal nanodisks shows stronger field enhancement and larger absorption, extinction, and scattering cross sections in its dipole resonance wavelength, which is defined as a bright plasmonic mode. In addition, some weaker resonant modes are observed for both structures and the reason for their generation is dis-cussed. The analysis of different possible modes in such structures is crucial for their application in various fields. Plasmon ; Materials science ; Optoelectronics ; Nanostructure ; Nanotechnology ; Optics ; Physics Optical Coatings and Gratings ; Photonic Crystals and Applications ; Plasmonic and Surface Plasmon Research
Authors: Djamal Gacemi | Baptiste Chomet | Olivier Lopez | Livia Del Balzo | Angela Vasanelli | Jérôme Faist | Benoît Darquié | Carlo Sirtori
Source:  (article, 2024-09-01)
Field: Chemistry — Spectroscopy

Active linewidth narrowing of a 8.1µm Quantum cascade laser to a mid-IR frequency comb In this work we demonstrate a phase-lock of a single-mode continuous-wave Fabry-Perot quantum cascade laser (QCL) emitting at 8.1 μm to a low-noise mid-Infrared (mid-IR) optical frequency comb. The stability of the comb used as a reference is transferred to the QCL resulting in an integrated residual phase error of 0.4 rad. The laser linewidth is narrowed by more than two orders of magnitude reaching 300 Hz at 1ms observation time, limited by the spectral purity of the mid-IR comb. Laser linewidth ; Quantum cascade laser ; Cascade ; Frequency comb ; Laser ; Optoelectronics ; Optics ; Quantum ; Physics ; Materials science ; Chemistry ; Quantum mechanics Spectroscopy and Laser Applications ; Advanced Fiber Laser Technologies ; Laser Design and Applications
Authors: Yuki Miyamoto | A. Hiramoto | Kana Iwakuni | Susumu Kuma | Katsunari Enomoto | Naofumi Nakayama | Masaaki Baba
Source: The Journal of Chemical Physics (article, 2024-04-09)
Field: Materials Science — Materials Chemistry

Analysis on high-resolution spectrum of the <i>S</i>1–<i>S</i>0 transition of free-base phthalocyanine A high-resolution absorption spectrum of the S1-S0 transition of free-base phthalocyanine was observed and analyzed with improved reliability. The spectrum, with a partially resolved rotational structure, was obtained by using the buffer-gas cooling technique and a single-mode tunable laser. Our new analysis reveals that the S1←S0000 band belongs to the a-type transition, where the electronic transition moment aligns parallel to the NH-HN direction, allowing the assignment of the S1 state to 1B3u. These results agree with a prior study using supersonic expansion and are well supported by theoretical calculations. Interestingly, the rotational constant B in the S1 state, which is often smaller than that in the ground state for typical molecules, was found to be slightly larger than that in the S01Ag state. This suggests a change in the character of π bonds with the electronic excitation. Ground state ; Molecular electronic transition ; Phthalocyanine ; Chemistry ; Transition dipole moment ; Supersonic speed ; Absorption spectroscopy ; Excitation ; Atomic physics ; Electronic structure ; Molecule ; Molecular physics ; Materials science ; Physics ; Computational chemistry ; Optics Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies ; Advanced Chemical Physics Studies
Authors: Jovana Periša | Sanja Kuzman | Aleksandar Ćirić | Zoran Ristić | Željka Antić | Miroslav D. Dramićanin | Bojana Milićević
Source: Nanomaterials (article, 2024-10-10)
Field: Materials Science — Materials Chemistry

Tuneable Red and Blue Emission of Bi3+-Co-Doped SrF2:Eu3+ Nanophosphors for LEDs in Agricultural Applications Tunable blue/red dual-emitting Eu<sup>3+</sup>-doped, Bi<sup>3+</sup>-sensitized SrF<sub>2</sub> phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (<i>Fm</i>-<i>3m</i> (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi<sup>3+</sup> concentration in SrF<sub>2</sub>: Eu<sup>3+</sup> phosphor increases. Under the 265 nm excitation, photoluminescence spectra show emission at around 400 nm from the host matrix and characteristic orange <sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>1,2</sub> and deep red <sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>4</sub> Eu<sup>3+</sup> emissions. The red emission intensity increases with an increase in Bi<sup>3+</sup> concentration up to 20 mol%, after which it decreases. The integrated intensity of Eu<sup>3+</sup> red emission in the representative 20 mol% Bi<sup>3+</sup> co-doped SrF<sub>2</sub>:10 mol% Eu<sup>3+</sup> shows twice as bright emission compared to the Bi<sup>3+</sup>-free sample. To demonstrate the potential application in LEDs for artificial light-based plant factories, the powder with the highest emission intensity, SrF<sub>2</sub>: 10Eu, 20 Bi, was mixed with a ceramic binder and placed on top of a 275 nm UVC LED chip, showing pinkish violet light corresponding to blue (409 nm) and red (592, 614, and 700 nm) phosphors' emission. Phosphor ; Materials science ; Light-emitting diode ; Photoluminescence ; Emission spectrum ; Analytical Chemistry (journal) ; Doping ; Emission intensity ; Luminescence ; Optoelectronics ; Spectral line ; Chemistry Luminescence Properties of Advanced Materials ; Ammonia Synthesis and Nitrogen Reduction ; Radiation Detection and Scintillator Technologies
Authors: José Ramón Serrano | Pedro Piqueras | Enrique José Sanchís | Carla Conde
Source: Applied Sciences (article, 2024-05-31)
Field: Materials Science — Materials Chemistry

Analysis of Altitude and Ambient Temperature Effects on the Reactivity of Oxidation Catalysts in the Presence of H2 Worldwide emission standards are now required to cover engine operation under extreme ambient conditions, which affect the raw emissions and the efficiency of the exhaust aftertreatment systems. These regulations also target new combustion technologies for decarbonization, such as neat hydrogen (H2) combustion or dual-fuel strategies, which involve a challenge to the analysis of exhaust aftertreatment system requirements and performance. This work addresses the impact of high altitude and low ambient temperature conditions on the reactivity of an oxidation catalyst in the presence of H2. A reaction mechanism is proposed to cover the main conversion paths of CO, HC, and H2, including the formation and consumption of high-energy surface reaction intermediates. The mechanism has been implemented into a faster-than-real-time reduced-order model for multi-layer washcoat honeycomb catalytic converters. The model was utilized to investigate the effect of H2 concentration on the reactivity of CO and HC within the catalyst under various operating and ambient conditions. By applying the model and examining the selectivity towards different reaction pathways in the presence of H2, insights into surface intermediates and reactivity across different cross-sections of the monolith were obtained. This analysis discusses the underlying causes of reactivity changes promoted by H2 and its relative importance as a function of driving boundary conditions. Reactivity (psychology) ; Catalysis ; Combustion ; Chemical engineering ; Monolith ; Materials science ; Work (physics) ; Chemistry ; Environmental science ; Physical chemistry ; Mechanical engineering ; Organic chemistry ; Engineering Catalytic Processes in Materials Science ; Advanced Combustion Engine Technologies ; Vehicle emissions and performance
Authors: Cullen Greer | Zackary R. Kinlein | Brian H. Clowers
Source: Rapid Communications in Mass Spectrometry (article, 2024-08-26)
Field: Chemistry — Spectroscopy

Ion confinement and separation using asymmetric electrodynamic fields in structures for lossless ion manipulations A functional IMS instrument using asymmetric confining fields demonstrates additional field modifications may be a means to achieve additional functionality with limited interruption of the analysis. A TW-SLIM PCB specifically designed as a pusher board would benefit from minimized manufacturing cost, simplifying assembly, reducing drive electronics, and improved field consistency. Ion ; Chemistry ; Electrode ; Electric field ; Planar ; Range (aeronautics) ; Faraday cage ; Transmission (telecommunications) ; Optoelectronics ; Optics ; Physics ; Materials science ; Electrical engineering ; Magnetic field ; Engineering Mass Spectrometry Techniques and Applications ; Microfluidic and Capillary Electrophoresis Applications ; Analytical Chemistry and Sensors
Authors: Samuel P. Brown | Ryan J. Lawson | Jonathan D. Moreno | Joseph L. Ransdell
Source: Journal of Neuroscience (article, 2024-06-10)
Field: Chemistry — Electrochemistry

A Reinterpretation of the Relationship between Persistent and Resurgent Sodium Currents The resurgent sodium current (I<sub>NaR</sub>) activates on membrane repolarization, such as during the downstroke of neuronal action potentials. Due to its unique activation properties, I<sub>NaR</sub> is thought to drive high rates of repetitive neuronal firing. However, I<sub>NaR</sub> is often studied in combination with the persistent or noninactivating portion of sodium currents (I<sub>NaP</sub>). We used dynamic clamp to test how I<sub>NaR</sub> and I<sub>NaP</sub> individually affect repetitive firing in adult cerebellar Purkinje neurons from male and female mice. We learned I<sub>NaR</sub> does not scale repetitive firing rates due to its rapid decay at subthreshold voltages and that subthreshold I<sub>NaP</sub> is critical in regulating neuronal firing rate. Adjustments to the voltage-gated sodium conductance model used in these studies revealed I<sub>NaP</sub> and I<sub>NaR</sub> can be inversely scaled by adjusting occupancy in the slow-inactivated kinetic state. Together with additional dynamic clamp experiments, these data suggest the regulation of sodium channel slow inactivation can fine-tune I<sub>NaP</sub> and Purkinje neuron repetitive firing rates. Reinterpretation ; Philosophy Electrochemical Analysis and Applications
Authors: Lincon Coutinho Marins | Alessandra Maffei Monteiro | Vivane Lopes Leal | Deyber Arley Vargas Medina | Edwin Martin Cárdenas Contreras | Fernando Mauro Lanças
Source: Separations (article, 2024-12-30)
Field: Chemistry — Spectroscopy

A Compact Instrument for Temperature-Programming-Assisted Capillary–Nanoliquid Chromatography The miniaturization of liquid chromatography (LC) columns to capillary and nanoscales allows temperature programming to be an effective alternative to solvent gradients for modulating eluotropic strength. This approach simplifies instrument design and operation, as a single pump can suffice to achieve efficient separations. This study presents the development and application of a compact, lab-built high-pressure system for temperature-programmed capillary and nanoLC separations. The instrument includes a high-pressure capillary–nanoflow syringe pump, a time-based nanoliter injection system, a programmable capillary column oven for controlled temperature gradients, and a UV-Vis detection system with a custom nanoliter-scale detection cell. Each system component was designed and built in-house, with rigorous calibration to ensure accuracy and operational reliability. Experimental data confirm the system’s capability to deliver precise, reproducible temperature, and flow rates. Functionality was validated through temperature-programmed separations on packed and open tubular capillary columns. The results demonstrated that the developed instrument offers enhanced separation efficiency and reduced analysis time compared to isothermal methods, underscoring its potential for advanced applications in miniaturized liquid chromatography. Capillary action ; Chromatography ; Chemistry ; Materials science ; Composite material Analytical Chemistry and Chromatography ; Microfluidic and Capillary Electrophoresis Applications ; Protein purification and stability
Authors: Zunqi Xiao | Zhizhong Jiang | Lin Luo | Yi Wan | Aixue Liu | Bin Zhang | Bing Ren | Jing Liu
Source: Coatings (article, 2024-10-28)
Field: Materials Science — Materials Chemistry

Protection of 316L Steel Against LBE Corrosion by a CaO-MgO-Al2O3-SiO2 Glass–Ceramic Coating A CaO-MgO-Al2O3-SiO2 glass–ceramic coating was prepared by the slurry method and subsequent sintering to improve the corrosion resistance of 316L steel in liquid lead–bismuth eutectic alloy at high temperatures. The glass–ceramic coating, sintered at 884 °C, was dense and demonstrated strong adhesion to the substrate. It was composed of the crystalline phases diopside (CaMgSi2O6) and anorthite (CaAl2Si2O8) and had an average Vickers hardness of 595 HV, which was over three times that of 316L steel. After corrosion in an oxygen-saturated, static lead–bismuth eutectic alloy at 500 °C for 1000 h, the uncoated 316L experienced significant mass gain (0.04 g) due to severe oxidative corrosion, resulting in the formation of Fe3O4 and Pb2O on its surface. In contrast, the glass–ceramic-coated specimens showed a very small mass gain (0.0012 g) after corrosion. The coating maintained good thermal stability; its crystalline phase composition remained largely unchanged after the corrosion test. The glass–ceramic coating still exhibited dense microstructure and tightly adhered to the substrate after corrosion. There was no evident penetration of lead–bismuth into the coating, and no dissolution of the coating’s elements into the lead–bismuth alloy was detected. These observations confirm that the glass–ceramic coating possessed superior corrosion resistance in liquid lead–bismuth eutectic environments. Materials science ; Corrosion ; Coating ; Metallurgy ; Ceramic ; Eutectic system ; Microstructure ; Alloy ; Dissolution ; Composite material ; Chemical engineering Nuclear Materials and Properties ; Nuclear materials and radiation effects ; Advanced ceramic materials synthesis
Authors: Alexander Haack | Christoph Schaefer | Stefan Zimmermann
Source: Analytical Chemistry (article, 2024-07-15)
Field: Chemistry — Spectroscopy

On the Arrival Time Distribution of Reacting Systems in Ion Mobility Spectrometry Ion mobility spectrometry (IMS) is a widely used gas-phase separation technique, particularly when coupled with mass spectrometry (MS). Modern IMS instruments often apply elevated reduced field strengths for improved ion separation and ion focusing. These alter the collision dynamics and further drive ion reaction processes that can change the analyte's structure. As a result, the measured arrival time distribution (ATD) can change with the applied reduced field strengths. In this work, we systematically study how the ion collision dynamics and the ion reaction dynamics, as a function of the reduced field strength, can alter the ATD. To this end, we investigate 2,6-di-<i>tert</i>-butylpyridine, methanol, and ethyl acetate using a home-built drift tube IMS coupled to a home-built MS and extensive first-principles Monte Carlo modeling. We show how elevated reduced field strengths can actually lower resolving power through increased ion diffusion and how the field dependency of the ion mobility can introduce uncertainties to collision cross sections (CCS) calculated from the measured mobilities. On top of the collision dynamics, we show how chemical transformation processes that alter the analyte's CCS, e.g., dynamic clustering or fragmentation, can lead to broadened, shifted, or non-Gaussian ATDs and how sensitive these processes are to the applied field strengths. We highlight how first-principles ion dynamics simulations can help to understand and even harness the mentioned effects. Ion-mobility spectrometry ; Chemistry ; Ion ; Mass spectrometry ; Fragmentation (computing) ; Field (mathematics) ; Analyte ; Diffusion ; Chemical physics ; Analytical Chemistry (journal) ; Chromatography ; Physics ; Computer science ; Thermodynamics Mass Spectrometry Techniques and Applications ; Analytical Chemistry and Chromatography ; Analytical chemistry methods development
Authors: Guanghui He | Bingtian Ye | Ruotian Gong | Changyu Yao | Zhongyuan Liu | Kater Murch | Norman Y. Yao | Chong Zu
Source: arXiv (Cornell University) (preprint, 2024-03-26)
Field: Materials Science — Materials Chemistry

Experimental Realization of Discrete Time Quasi-Crystals Floquet (periodically driven) systems can give rise to unique non-equilibrium phases of matter without equilibrium analogs. The most prominent example is the realization of discrete time crystals. An intriguing question emerges: what other novel phases can manifest when the constraint of time periodicity is relaxed? In this study, we explore quantum systems subjected to a quasi-periodic drive. Leveraging a strongly interacting spin ensemble in diamond, we identify the emergence of long-lived discrete time quasi-crystals. Unlike conventional time crystals, time quasi-crystals exhibit robust sub-harmonic responses at multiple incommensurate frequencies. Furthermore, we show that the multi-frequency nature of the quasi-periodic drive allows for the formation of diverse patterns associated with different discrete time quasi-crystalline phases. Our findings demonstrate the existence of non-equilibrium phases in quasi-Floquet settings, significantly broadening the catalog of novel phenomena in driven many-body quantum systems. Realization (probability) ; Computer science ; Mathematics ; Statistics Quasicrystal Structures and Properties