On the transfer of theoretical multipole parameters for restoring static electron density and revealing and treating atomic anharmonic motion. Features of chemical bonding in crystals of an isocyanuric acid derivative

The crystal and electronic structure of an isocyanuric acid derivative was studied by high-resolution single-crystal X-ray diffraction within the Hansen–Coppens multipole formalism. The observed deformation electron density shows signs of thermal smearing. The experimental picture meaningfully assigned to the consequences of unmodelled anharmonic atomic motion. Straightforward simultaneous refinement of all parameters, including Gram–Charlier coefficients, resulted in more significant distortion of apparent static electron density, even though the residual density became significantly flatter and more featureless. Further, the method of transferring multipole parameters from the model refined against theoretical structure factors as an initial guess was employed, followed by the subsequent block refinement of Gram–Charlier coefficients and the other parameters. This procedure allowed us to appropriately distinguish static electron density from the contaminant smearing effects of insufficiently accounted atomic motion. In particular, some covalent bonds and the weak π...π interaction between isocyanurate moieties were studied via the mutual penetration of atomic-like kinetic and electrostatic potential φ-basins with complementary atomic ρ-basins. Further, local electronic temperature was applied as an advanced descriptor for both covalent bonds and noncovalent interactions. Total probability density function (PDF) of nuclear displacement showed virtually no negative regions close to and around the atomic nuclei. The distribution of anharmonic PDF to a certain extent matched the residual electron density from the multipole model before anharmonic refinement. No signs of disordering of the sulfonyl group hidden in the modelled anharmonic motion were found in the PDF.

Elementary Charge and Electron: One Entity Two Identities

Our knowledge of electricity is based on two nearly parallel concepts – charge and electron. The charge concept is symmetrical: nature has equal numbers of positive and negative charges playing equivalent roles in atoms. The electron concept has two asymmetries. One, the observable universe has more positive than negative electrons. Two, atoms contain negative- but no positive electrons. Here I propose that charge is static electron and electron is moving charge. That is, resting (electrostatic) and moving (electrodynamic) behaviours exclusively make charge and electron different. The proposal reveals previously unnoticed symmetries in the electron concept and has experimental backing. Faraday, Stoney and Millikan observed charges in static conditions – electrolytes, oil drops, doorknobs etc. In contrast, Thomson and Anderson observed electrons at high speeds in cathode tubes and cloud chambers. Beta decays were initially interpreted to mean existence of electrons in atomic nuclei[i]. Equating ‘charge’ to ‘static electron’ reinstates and validates the interpretation. Brown, L. M. Nuclear structure and beta decay (1932–1933), American Journal of Physics 56, 982 (1988).

Laws of Gravity and Electrostatics Reduce Elementary Particles to Only Two: Positron and Negatron

I demonstrate that the macrocosmic gravitational interaction between two masses and the microcosmic electrostatic interaction between two charges unify in simple concepts and mathematical laws when electric charge and ordinary mass are interpreted in reciprocal terms. No previous research has ever attempted to unify charge and mass. The difficulty has been lack of an intelligible definition of charge. A three-point paradigm shift solves the problem, giving convincing evidence – for the first time – that positron and negatron are the ultimate elementary particles. That is, matter is pure positive and negative grains of electricity. Paradigm shift #1: Electron is a moving charge; a charge is static electron – ‘one entity two identities’. This implies that ordinary matter contains equal numbers of positive and negative electrons – observed in motion as ‘electrons’ and at rest as ‘charges’. In motion, a positron-negatron pair obeys the laws of electrodynamics and annihilates; at rest, the pair obeys the laws of electrostatics and neutralizes. Paradigm shift #2: Electron mass and electrostatic field are either positive or negative. Opposite masses and fields, rather than indefinable ‘charge’, make opposite electrons physically different. Paradigm shift #3: Electric charge and ordinary mass interconvert. Positive charge (e+) and negative charge (e-) neutralize to neutral charge (2e0), which is nature’s quantum of ordinary mass. Conversely, a quantum of ordinary mass splits to opposite charges e.g. in frictional electrification. The insights systematize the search, identification and classification of ‘elementary particles’, ending decades of confusion in the ‘elementary particle zoo’. They identify a new, stable subatomic particle – a third nucleon.

Interfacial Hydroxyl Promotes the Reduction of 4 Nitrophenol by Ag-Based Catalysts Confined in Dendritic Mesoporous Silica Nanospheres

Surface states—the electronic states emerging as a solid material terminates at a surface—are usually vulnerable to contaminations and defects. This fundamental limitation has prohibited systematic studies of the potential role of surface states in surface reactions and catalysis, especially in more realistic environments. We use the selective reduction of 4-Nitrophenol on silver-covered dendritic mesoporous silica nanospheres (DMSNs) as a prototype example, and show that the dynamic intermediate surface states (DISS) spatially formed by spin orbital coupling (SOC) in singly hydrated hydroxyl complex can significantly enhance the adsorption energy of both 4-Nitrophenol and BH4- anions, by promoting different directions of static electron transfer. The concept of DISS as an electron bath may lead to new design principles beyond the conventional d-band theory of heterogeneous catalysis.

Interfacial Hydroxyl Promotes the Reduction of 4 Nitrophenol by Ag-Based Catalysts Confined in Dendritic Mesoporous Silica Nanospheres

Surface states—the electronic states emerging as a solid material terminates at a surface—are usually vulnerable to contaminations and defects. This fundamental limitation has prohibited systematic studies of the potential role of surface states in surface reactions and catalysis, especially in more realistic environments. We use the selective reduction of 4-Nitrophenol on silver-covered dendritic mesoporous silica nanospheres (DMSNs) as a prototype example, and show that the dynamic intermediate surface states (DISS) spatially formed by spin orbital coupling (SOC) in singly hydrated hydroxyl complex can significantly enhance the adsorption energy of both 4-Nitrophenol and BH4- anions, by promoting different directions of static electron transfer. The concept of DISS as an electron bath may lead to new design principles beyond the conventional d-band theory of heterogeneous catalysis.

Nanoscopic Structural Fluctuations of Disassembling Microtubules Revealed by Label-Free Super-Resolution Microscopy

Microtubules are cytoskeletal polymers of tubulin dimers assembled into protofilaments that constitute nanotubes undergoing periods of assembly and disassembly. Static electron micrographs suggest a structural transition of straight protofilaments into curved ones occurring at the tips of disassembling microtubules. However, these structural transitions have never been observed and the process of microtubule disassembly thus remains unclear. Here, a label-free optical microscopy capable of selective imaging of the transient structural changes of protofilaments at the tip of a disassembling microtubule is introduced. Upon induced disassembly, the transition of ordered protofilaments into a disordered conformation is resolved at the tip of the microtubule. Imaging the unbinding of individual tubulin oligomers from the microtubule tip reveals transient pauses and relapses in the disassembly, concurrent with enrichment of ordered protofilament segments at the microtubule tip. These findings show that microtubule disassembly is a discrete process and suggest a mechanism of switching from the disassembly to the assembly phase.

Modeling Ionospheric Densities and Flows in Crustal and Draped Magnetic Fields at Mars

<p>NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) explorer has been in orbit around Mars for over 5 years now, collecting valuable data about the planet. Specifically, the Langmuir Probe and Waves (LPW), the Neutral Gas and Ion Mass Spectrometer (NGIMS), and the Suprathermal and Thermal Ion Composition (STATIC) instruments measure important ionospheric properties. The instruments measure electron densities and temperature (LPW), neutral gas and ion composition (NGIMS), and the properties of escaping ions (STATIC). Electron and ion density and flux measurements are presented. The data indicates significant differences in ion properties between open crustal, closed crustal, and draped magnetic fields. Similar differences are noted for electrons as well. An ionospheric model has been developed that produces a profile of the ionosphere. The model then explores the evolution of the ionosphere, via chemistry and transport. At low altitudes (z<300 km), chemistry dominates, while transport dominates at higher altitudes. Results show significant differences in the ionosphere between the types of fields. The model utilizes data from the Magnetometer (MAG) instrument to provide properties of magnetic fields at Mars. The model may also help explain some of the atmospheric loss occurring at Mars. This is compared to data from STATIC. Analytic arguments for subsonic vs supersonic flow speeds (in the open field case) are also presented.</p>