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We have analyzed the role of auroral processes in the formation of the outer radiation belt, considering that the main part of the auroral oval maps to the outer part of the ring current, instead of the plasma sheet as is commonly postulated. In this approach, the outer ring current is the region where transverse magnetospheric currents close inside the magnetosphere. Specifically, we analyzed the role of magnetospheric substorms in the appearance of relativistic electrons in the outer radiation belt. We present experimental evidence that the presence of substorms during a geomagnetic storm recovery phase is, in fact, very important for the appearance of a new radiation belt during this phase. We discuss the possible role of adiabatic acceleration of relativistic electrons during storm recovery phase and show that this mechanism may accelerate the relativistic electrons by more than one order of magnitude.

Practical interest in oxygen reduction reaction (ORR) has traditionally been due to its application at fuel cells’ cathode following its complete 4e route to the water. In search of new electrode materials, it was discovered that conducting polymers (CPs) also are capable of driving ORR, though predominantly halting the process at 2e reduction leading to hydrogen peroxide generation. As alternative ways to produce this “green oxidant” are attracting increasing attention, a detailed study of the ORR mechanism at CP electrodes gains importance. Here, we summarize our recent theoretical work on the topic, which underscores the fundamental difference between CP and electrocatalytic metal ORR electrodes. Our insights also bring to us the attention of outer‐sphere electron transfer, not unknown but somewhat ignored in the field. We also put the action of CP electrodes in a more general context of chemical ORR and redox mediation responsible for the electrocatalytic ORR mechanism.

Magnetic reconnection is a fundamental physical process of rapidly converting magnetic energy into particles. The electron diffusion region (EDR) is the crucial region during magnetic reconnection. The outer EDR, which also plays a crucial role in magnetic reconnection, is responsible for energy conversion. In the outer EDR, the electrons are decelerated and return the energy to the magnetic field on the pileup region behind the reconnection front. In the present study, we used the fully kinetic particle‐in‐cell simulation and revealed that part of decelerated electrons in the outer EDR could even move back to the inner EDR. This phenomenon is caused by the dominant contribution from the magnetic tension force, and it suggests a magnetic Marangoni effect in space plasma, similar to the Marangoni effect in fluids. Our results potentially propose a brand‐new physical process and a novel mechanism in the EDR during magnetic reconnection. Plain Language Summary Plasma's energy can be changed through various approaches in the universe, and magnetic reconnection is one of those approaches to convert energy from the magnetic field to the plasma. In the reconnection site, the inner electron diffusion region (EDR) is an essential area where the energy is released, and the electron's energy is enhanced significantly. Meanwhile, in the outer EDR, the electrons are decelerated by the electric field, thus their energy decreases. However, part of those electrons can move backward to the inner EDR, and how this phenomenon comes up has no further investigation. In this study, we use numerical simulations to reveal the possible mechanism of this kind of electron's motion. It is found that the electron deceleration is caused by the magnetic tensor force. The electrons with specific conditions have the possibility to move backward. Those backflow electrons have a second chance to be accelerated again in the inner EDR. Such electron motion in plasma physics is not a kind of gyro movement but might indicate a so‐called magnetic Marangoni effect similar to the Marangoni effect in fluid physics. Our findings propose a novel mechanism associated with electron acceleration in the EDR during magnetic reconnection. Key Points The magnetic tension force causes the deceleration of the electrons in the outer electron diffusion region (EDR) during magnetic reconnection Partial electrons are decelerated and even move back to the inner EDR, and they are accelerated again and attain higher energy The electron backflow motion in the outer EDR indicates a magnetic Marangoni effect in space plasma

The linear relations between adsorption energies are one of the cornerstones of contemporary catalysis in view of the simplicity and predictive power of the computational models built upon them. Despite their extensive use, the exact nature of scaling relations is not yet fully understood, and a comprehensive theory of scaling relations is yet to be elaborated. So far, it is known that scalability is dictated by the degree of resemblance of the adsorbed species. In this work, density functional theory calculations show that CO and OH, two dissimilar species, scale or not depending on the surface facet where they adsorb at Pt alloys. This peculiar behavior arises from an interplay of ligand and geometric effects that can be used to modulate adsorption‐energy scalability. This study opens new possibilities in catalysis, as it shows that surface coordination is a versatile tool to either balance or unbalance the similarities among adsorbates at alloy surfaces. Currently, it is widely accepted that adsorption‐energy scaling relations exist or not depending on the similarity of the adsorbates. Here, we show that CO and OH scale linearly or not on Pt alloys depending on the coordination of the adsorption sites. Hence, ligand and geometric effects can be used to modulate scaling relations, thereby opening new possibilities in catalysis.

Field‐line curvature scattering (FLCS) is believed to be the primary mechanism forming electron isotropy boundaries (IB) and can rapidly scatter relativistic electrons from the outer radiation belt. However, its direct and quantitative impact on controlling outer belt electron lifetimes has never been directly assessed. Using simultaneous observations of IBs from low‐altitude satellites and in situ electron fluxes from equatorial satellites, we report IBs intruding into the outer belt (reaching L ∼ 4.5), closely synchronized with sharp flux radial gradients near IBs, caused by significant electron loss outside IBs during a 4‐day storm recovery period. By combining observations with simulations, we provide the first direct and quantitative evidence that FLCS‐induced electron loss outside the IB dominantly controls the outer belt electron lifetimes. Our findings reveal that this simple yet fundamental physical process, which has been historically neglected in global radiation belt models, can explain the outer electron belt configuration.

The paper shows that the values of zero-point energy and vibrations of atoms in a crystal determined by the uncertainty principle, depend on the dynamic response of atoms. It is found that the root-mean-square (rms) amplitude of thermal and zero-point vibrations of atoms in crystal lattices of elements from the periodic table, has a periodic dependence on the atomic number of elements. It is shown that the rms amplitude of thermal vibrations of atoms in crystal lattices of elements with high Debye temperature, does not strongly differ from their zero-point vibrations at room temperature. This is explained by a small number of excited vibrations with the maximum frequency at room temperature, since the latter is significantly lower than their Debye temperature, at which the whole range of thermal vibrations of atoms in the crystal excites. The obtained results can be used in materials science and technology to estimate the strength and thermal characteristics of materials at cryogenic temperatures, without their direct measurements at the absolute-zero temperature.

Iron phthalocyanine (FePc) was penta‐coordinated with pyridine ligand (Py) grafted on carbon nanotube (CNT), to form (FePc‐Py‐CNT). The complex was studied as a catalyst for the oxygen reduction reaction ORR in seven different supporting electrolytes: OH− (0.1 M), OH− (1 M), NO3− (1 M), HSO4− (1 M), ClO4− (1 M), Br− (1 M), Cl− (1 M), to unveil anion‐poisoning effects and mechanism. Through cyclic voltammetry and polarization curves in N2 and O2 saturated atmospheres, thermodynamic and kinetic data were acquired. In acid media, the formal potential Fe(III)/(II) (E0’Fe(III)/(II)) of the complex is biased to more negative potentials by the anion presence. Similar effects were observed for the onset potential (Eonset) during polarization curves for the ORR. When the ORR was performed in the presence of either ClO4−, or HSO4−, anions, Tafel analysis showed different values depending if were derived from the low or from the high overpotential regions, revealing an inner‐sphere electron transfer mechanism (ISET). The Tafel values derived from measurements in the presence of Cl− and Br− anions do not change when extracted at low or at high overpotentials evidencing an outer‐sphere reaction mechanism (OSET). Gibbs free energies were derived from poisoning tests confirming the ISET and OSET mechanisms. The poisoning effect is responsible for the immediate loss of performance for these catalysts during the ORR in acidic media. Iron phthalocyanine is penta‐coordinated with pyridine ligand grafted on carbon nanotubes. The complex is studied as a catalyst for the oxygen reduction reaction in different supporting electrolytes to unveil anion‐poisoning effects and mechanisms. The poisoning effect is responsible for the immediate loss of performance during the ORR in acidic media.

Electronic absorption spectroscopy was used to study the ETR of surfactant–cobalt(III) complexes containing imidazo[4,5-f][1,10]phenanthroline, dipyrido[3,2-d:2′-3′-f]quinoxaline and dipyrido[3,2-a:2′,4′-c](6,7,8,9-tetrahydro)phenazine ligands by using ferrocyanide ions in unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC) and 1-butyl-3-methylimidazolium bromide ((BMIM)Br), at different temperatures under pseudo-first-order conditions using an excess of the reductant. The reactions were found to be second-order and the electron transfer is postulated as occurring in the outer sphere. The rate constant for the electron transfer reactions was found to increase with increasing concentrations of ionic liquids. Besides these, the effects of surfactant complex ions on liposome vesicles in these same reactions have also been studied on the basis of hydrophobicity. We observed that, below the phase transition temperature, there is an increasing amount of surfactant–cobalt(III) complexes expelled from the interior of the vesicle membrane through hydrophobic effects, while above the phase transition temperature, the surfactant–cobalt(III) complexes are expelled from the interior to the exterior surface of the vesicle. Kinetic data and activation parameters are interpreted in respect of an outer-sphere electron transfer mechanism. By assuming the existence of an outer-sphere mechanism, the results have been clarified based on the presence of hydrophobicity, and the size of the ligand increases from an ip to dpqc ligand and the reactants become oppositely charged. In all these media, the ΔS# values are recognized as negative in their direction in all the concentrations of complexes employed, indicative of a more ordered structure of the transition state. This is compatible with a model in which these complexes and [Fe(CN)6]4− ions bind to the DPPC in the transition state. Thus, the results have been interpreted based on the self-aggregation, hydrophobicity, charge densities of the co-ligand and the reactants with opposite charges.

The coenzyme nicotinamide adenine dinucleotide (NADH) undergoes facile electron transfer reaction with vanadium (V) substituted Keggin-type heteropolyanions (HPA) [PVVW11O40]4− (PV1) and [PVV2W10O40]5− (PV2) in aqueous phosphate buffer of pH 6 at ambient temperature. Electrochemical and optical studies show that the stoichiometry of the reaction is 1: 2 (NADH: HPA). EPR and optical studies show that HPA act as one electron acceptor and the products of electron transfer reactions are one electron reduced heteropoly blues (HPB), viz. [PVIVW11O40]5− and [PVIVVVW10O40]6−. Oxygraph measurements show that there is no uptake of molecular oxygen during the course of reaction. The reaction proceeds through multi-step electron-proton-electron transfer mechanism, with rate limiting initial one electron transfer from NADH to HPA by outer sphere electron transfer process. Bimolecular rate constant for electron transfer reaction between NADH and PV2 in phosphate buffer of pH = 6 has been determined spectrophotometrically.

Rates of electron transfer reaction of thioglycolic acid with vanadium(V) substituted Keggin-type heteropolyanion, [PVVVVW10O40]5−, in acetate-acetic acid buffers have been measured spectrophotometrically at 25°C. The order of the reaction with respect to substrate and oxidant is unity. The reaction shows simple second order kinetics at constant pH. The rate of the reaction increases with increase of pH of the medium. The mono-anion HSCH2COO− and di-anion −SCH2COO− are found to be the reactive species. Rate constants for mono-anion and di-anion are evaluated from rate law derived from the mechanism. By applying Rehm-Weller relationship, self exchange rate constant for the −SCH2COO−/\\( S^ \\)CH2COO− couple was evaluated as 3·3 × 103 dm3 mol−1 s−1 at 25°C.