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Nitric oxide (NO) radicals are ubiquitous chemical intermediates present in the atmosphere and in combustion processes, where laser-induced fluorescence is extensively used on the NO (A2Σ+ ← X2Π) band to report on fuel-burning properties. However, accurate fluorescence quantum yields and NO concentration measurements are impeded by electronic quenching of NO (A2Σ+) to NO (X2Π) with colliding atomic and molecular species. To improve predictive combustion models and develop a molecular-level understanding of NO (A2Σ+) quenching, we report the velocity map ion images and product state distributions of NO (X2Π, v″ = 0, J″, Fn, Λ) following nonreactive collisional quenching of NO (A2Σ+) with molecular oxygen, O2 (X3Σg−). A novel dual-flow pulse valve nozzle is constructed and implemented to carry out the NO (A2Σ+) electronic quenching studies and to limit NO2 formation. The isotropic ion images reveal that the NO–O2 system evolves through a long-lived NO3 collision complex prior to formation of products. Furthermore, the corresponding total kinetic energy release distributions support that O2 collision coproducts are formed primarily in the c1Σu− electronic state with NO (X2Π, v″ = 0, J″, Fn, Λ). The product state distributions also indicate that NO (X2Π) is generated with a propensity to occupy the Π(A″) Λ-doublet state, which is consistent with the NO π* orbital aligned perpendicular to nuclear rotation. The deviations between experimental results and statistical phase space theory simulations illustrate the key role that the conical intersection plays in the quenching dynamics to funnel population to product rovibronic levels. [ABSTRACT FROM AUTHOR]

Optical transitions in atomically thin MoS2 samples made by sulfidation of a metallic molybdenum layer have been studied by photoreflectance (PR) and photoacoustic (PA) spectroscopy. The obtained spectra are compared with PR and PA spectra of bulk MoS2. It is shown that the absorption edge observed in the PA spectrum shifts to blue when moving from the bulk MoS2 to the atomically thin MoS2 layers, whereas the direct optical transitions at the K point of the Brillouin zone (A and B transitions), which are observed in the PR spectrum, do not shift spectrally in a significant manner. On the other hand, the AH transition, which is related to the direct optical transition at the H point of the Brillouin zone and is typical of bulk MoS2, is not observed for atomically thin MoS2 layers. Moreover, a strong and broad PR resonance related to the band nesting (C transition) is identified in the PR spectra of studied samples. In this case, C and CH transitions are observed for bulk MoS2, while only a C transition is observed for atomically thin MoS2. [ABSTRACT FROM AUTHOR]

Hub–filament systems are suggested to be the birth cradles of high-mass stars and clusters, but the formation of hub–filament structure is still unclear. Using FUGIN 13CO (1–0), C18O (1–0) and SEDIGISM 13CO (2–1) survey data, we investigate the formation of hub–filament structure in the W33 complex. The W33 complex consists of two colliding clouds, called W33-blue and W33-red. We decompose the velocity structures in W33-blue by fitting multiple velocity components and find a continuous and monotonic velocity field. Virial parameters of Dendrogram structures suggest the dominance of gravity in W33-blue. The strong positive correlation between velocity dispersion and column density indicates that the non-thermal motions in W33-blue may originate from gravitationally driven collapse. These signatures suggest that the filamentary structures in W33-blue result from the gravitational collapse of a compressed layer. However, the large-scale velocity gradient in W33-blue may originate mainly from cloud–cloud collision and feedback of active star formation, instead of filament-rooted longitudinal inflow. From the results observed above, we argue that cloud–cloud collision triggers the formation of hub–filament structures in the W33 complex. Meanwhile, the appearance of multiple-scale hub–filament structures in W33-blue is likely an imprint of the transition from a compressed layer to a hub–filament system. [ABSTRACT FROM AUTHOR]

Translation of aberrant messenger RNAs can cause stalling of ribosomes resulting in ribosomal collisions. Collided ribosomes are specifically recognized to initiate stress responses and quality control pathways. Ribosome-associated quality control facilitates the degradation of incomplete translation products and requires dissociation of the stalled ribosomes. A central event is therefore the splitting of collided ribosomes by the ribosome quality control trigger complex, RQT, by an unknown mechanism. Here we show that RQT requires accessible mRNA and the presence of a neighboring ribosome. Cryogenic electron microscopy of RQT-ribosome complexes reveals that RQT engages the 40S subunit of the lead ribosome and can switch between two conformations. We propose that the Ski2-like helicase 1 (Slh1) subunit of RQT applies a pulling force on the mRNA, causing destabilizing conformational changes of the small ribosomal subunit, ultimately resulting in subunit dissociation. Our findings provide conceptual framework for a helicase-driven ribosomal splitting mechanism. Ribosome collisions serve as proxy for aberrant translation to initiate rescue and quality control pathways. Here, authors elucidate the molecular mechanism of collided ribosome clearance by the ribosome quality control trigger complex. [ABSTRACT FROM AUTHOR]

Using our recent concept of quasi‐molecule, we comment on the physical basis of the Periodic Table for the enumeration of Polyatomic Aromatic Hydrocarbons (PAH6), and Dias aufbau units on which it was based. The method here presented uses a mathematical Lemma and employs quantum chemistry calculations for the quasi‐molecules (tiles) that are embedded on the parent molecule: if planar, all tiles must be planar and share the same plane. Case studies include prototypical PAHs that originate from C10H8 by adding C3H or C4H2 aufbau units, some radicals like C17H11, members of the C3nHn+2m family, and [n]triangulenes. Although a demonstration by examples is impracticable due to number and time limitations, a simplified approach based on generalized quasi‐molecules is suggested. Apparently unreported thus far, the structures of a few novel planar molecules are presented, and so are difficulties often uncontested in assessing planarity via common quantum chemistry calculations. [ABSTRACT FROM AUTHOR]

The performance of 24 vdW‐DF functionals were evaluated. The calculated intermolecular interaction potentials for 11 complexes, which conatain O, S, Se, N, P, F, Cl and Br atoms, were compared with CCSD(T)/CBS level potentials to evaluate their accuracy. The performance depends on the choice of vdW‐functional significantly. The vdW‐DF3‐opt1 functional shows the best performance. The deviation ratios of calculated interaction energies of the complexes using the vdW‐DF3‐opt1 functional to CCSD(T) level interaction energies at the potential minima are −6 to 14 %. As a general tendency, the accuracy is improved in the order of vdW‐DF, vdW‐DF2, and vdW‐DF3, but even if they belong to the same group, the accuracy greatly differs depending on each functional. The calculations of hydrocarbon molecules show better performance compared with heteroatom containing molecules in most cases. The calculations using the vdW‐DF3‐opt1 functional and the best dispersion corrected DFT calculations show nearly identical performance. [ABSTRACT FROM AUTHOR]

In mini-review, deals with the theory of exciton quasimolecules in a nanosystem consisting of double quantum dots of germanium synthesized in a silicon matrix. An exciton quasimolecule was formed as a result of the interaction of two spatially indirect excitons. It is shown that, depending on the distance D between the surfaces of the quantum dots, spatially indirect excitons and of exciton quasimolecules was formed in the nanosystem. The binding energy of the singlet ground state of the exciton quasimolecule has been gigantic exceeding the binding energy of the biexciton in a silicon single crystal by almost two orders of magnitude. The emergence of a band of localized electron states in the band gap of the silicon matrix was found. This band of localized electron states appeared as a result of the splitting of electron levels in the chain of germanium quantum dots. [ABSTRACT FROM AUTHOR]

Observations of transitions between the hyperfine levels of the hydroxyl radical (OH) can provide crucial information on the physical conditions in interstellar clouds. Accurate modelling of the spectra requires calculated rate coefficients for the excitation of OH by H atoms, which is often present in molecular clouds in addition to the dominant H2 molecule. In this work, rate coefficients for the (de-)excitation of hyperfine levels of OH through collisions with hydrogen atoms are presented. In previous work, nuclear-spin-free scattering calculations were carried out; these took account of the fact that four electronic states (1 A ′, 1 A ″, 3 A ′, and 3 A ″) arise from the interaction of OH(X 2Π) with H(2 S). Because of the deep H2O(⁠|$\tilde{X}^1A^{\prime }$|⁠) well, inelastic transitions can occur through direct collisions or by formation and decay of a collision complex. The rates of collision-induced hyperfine transitions were computed by the recoupling method and the MJ randomization approximations, respectively. These data will be useful in astrophysical models of OH excitation. [ABSTRACT FROM AUTHOR]

Using the van der Waals density functional theory, we studied the binding peculiarities of favipiravir (FP) and ebselen (EB) molecules on a monolayer of black phosphorene (BP). We systematically examined the interaction characteristics and thermodynamic properties in a vacuum and a continuum, solvent interface for active drug therapy. These results illustrate that the hybrid molecules are enabled functionalized two-dimensional (2D) complex systems with a vigorous thermostability. We demonstrate in this study that these molecules remain flat on the monolayer BP system and phosphorus atoms are intact. It is inferred that the hybrid FP+EB molecules show larger adsorption energy due to the van der Waals forces and planar electrostatic interactions. The changes in Gibbs free energy at different surface charge fluctuations and temperatures imply that the FP and EB are allowed to adsorb from the gas phase onto the 2D film at high temperatures. Thereby, the results unveiled beneficial inhibitor molecules on two dimensional BP nanocarriers, potentially introducing a modern strategy to enhance the development of advanced materials, biotechnology, and nanomedicine. [ABSTRACT FROM AUTHOR]

This paper provides a multi-agent coordinated control system to improve the real-time performance of intelligent vehicle active collision avoidance. At first, the functions and characteristics of longitudinal and lateral collision avoidance agents are analyzed, which are the main components of the multi-agent. Then, a coordinated solution mechanism of an intelligent vehicle collision avoidance system is established based on hierarchical control and blackboard model methods to provide a reasonable way to avoid collision in complex situations. The multi-agent coordinated control system can handle the conflict between the decisions of different agents according to the rules. Comparing with existing control strategies, the proposed system can realize multi decisions and planning at the same time; thus, it will reduce the operation time lag during active collision avoidance. Additionally, fuzzy sliding mode control theory is introduced to guarantee accurate path tracking in lateral collision avoidance. Finally, co-simulation of Carsim and Simulink are taken, and the results show that the real-time behavior of intelligent vehicle collision avoidance can be improved by 25% through the system proposed. [ABSTRACT FROM AUTHOR]

Host–guest hybrid (HGH) consisting of p-But-calix[8]arene and fullerene C70 were fabricated with a facial solution deposition method. The as-prepared HGH samples are well periodic arranged in a layer structure, in which the interactions between the guest C70 and host p-Butcalix[8]arene molecules are van der Waals forces. High pressure Raman and UV–Vis absorption spectra studies on the HGH were recorded. Our results show that an orientational related phase transition and a one-dimensional (1D) polymerization of C70 molecules occur at about 2 and 7 GPa at room temperature, respectively. The band gap of the HGH translated synchronously with the change of structure upon compress. We suggest that the molecular confinement in such layer structure of the HGH restricts the polymerization of C70 molecules within a layer, which tunes the phase transition process of C70. This supplies a possible way to design fullerene-based functional materials at suitable conditions. [ABSTRACT FROM AUTHOR]

Pristine graphene is not suitable for hydrogen storage at ambient conditions since it binds the hydrogen molecules only by van der Waals interactions. However, the adsorption energy of the hydrogen molecules can be improved by doping or decorating metal atoms on the graphene monolayer. The doping and decoration processes are challenging due to the oxygen interference in hydrogen adsorption and the clustering issue of metal atoms. To improve the hydrogen adsorption energy in pristine graphene, we have explored the hydrogen storage capabilities of graphene monolayer in the presence of compressive strain. We found that at 6% of biaxial compressive strain, a 4*4*1 supercell of graphene can adsorb 10 H2 molecules above the graphene surface. The average binding energy of H2 for this configuration is found to be −0.42 eV/H2, which is very suitable for reversible hydrogen adsorption. We propose that a 4*4*1 supercell of graphene can adsorb a total number of 20 H2 molecules leading to a high hydrogen uptake of 9.4%. The interaction between orbitals of carbon and hydrogen atoms and the charge transfer process have been studied by plotting the partial density of states and surface charge density plots. The electronic density around the C–C bonds of graphene increases in the presence of compressive strain, due to which hydrogen molecules are strongly adsorbed. [ABSTRACT FROM AUTHOR]

It is a challenge to efficiently and accurately predict train dynamic responses during complex collisions. In this paper, a novel numerical simplification method for high-speed rail vehicles during complex impact configurations is proposed. The central section of high-speed rail vehicles is a sandwich corrugated hollow double-shell structure. Starting with a baseline detailed finite element (FE) model of a high-speed train, the central section was first simplified as a solid single-shell structure. A parametric study with various simplification thickness ratios of the simplified FE rail vehicle model in different longitudinal rigid-wall collisions and lateral rigid-cylinder impacts was then performed using LS-DYNA. Furthermore, a correlation and analysis (CORA) objective rating method was used to evaluate the related responses between the simplified and detailed baseline FE rail vehicle models. The results demonstrate that the simplified FE model could effectively predict the rail vehicle impact responses. The displacement and impact force time histories of the simplified vehicle model with a thickness ratio of 0.38 matched closely with the results of the baseline detailed FE model under both longitudinal and lateral impacts (total combined CORA rating score: 93%). The rail vehicle impact deformations of the simplified vehicle model were similar to those of the baseline detailed model. The application of the simplified vehicle FE model substantially reduced the computational time (approximately 55% reduction). This work provides a solid basis for efficiently exploring train impact responses in complex collisions, and will be especially useful for train occupant injury assessment. [ABSTRACT FROM AUTHOR]

The rigorous two-center approach based on the dual-kinetically balanced finite-basis-set expansion is applied to one-electron, heteronuclear diatomic Bi-Au, U-Pb, and Cf-U quasimolecules. The obtained 1 σ ground-state energies are compared with previous calculations, when possible. Upon analysis of three different placements of the coordinate system's origin in the monopole approximation of the two-center potential: (1) in the middle, between the nuclei, (2) in the center of the heavy nucleus, and (3) in the center of the light nucleus, a substantial difference between the results is found. The leading contributions of one-electron quantum electrodynamics (self-energy and vacuum polarization) are evaluated within the monopole approximation as well. [ABSTRACT FROM AUTHOR]

To address the issue of decision-making for ship collision avoidance in complex encounter situations, an Autonomous Collision Avoidance Decision-making (ACAD) model based on Attention Long Short-Term Memory Twin Delayed Deep Deterministic Policy Gradient (ATL-TD3) algorithm for Unmanned Surface Vessel (USV) is proposed in this study. The novelty of this method is: (1) Incorporating LSTM and multi-head self-attention mechanism into the existing TD3 algorithm network enhances its focus on pertinent historical state information. Furthermore, the generalization ability of the trained model is further enhanced through optimization of the accumulated experience. (2) A comprehensive reward mechanism is designed, incorporating ship domain, arena, yaw, and other relevant factors, which solve the encounters defined in clauses 13–17 in Chapter 2 of COLREGs and immediate danger. The experiment involved a comparative analysis of the average reward curve and success rate during training under different environments. Additionally, 20 cases of Imazu classic encounters and real navigation data from the Suez Canal were utilized to validate the proposed algorithm. It is highlight that the ACAD model trained by the ATL-TD3 algorithm exhibits remarkable performance in the generalization verification, surpassing conventional collision avoidance methods. • Incorporating LSTM and MHA mechanism into the existing TD3 algorithm network enhances its focus on pertinent historical state information. • The new reward function can solve the encounters in clauses 13–17 in Chapter 2 of COLREGs and immediate danger. [ABSTRACT FROM AUTHOR]

The low solubility of pea protein isolate (PPI) greatly limits its functional properties and its wide application in food field. Thus, this study investigated the effects and mechanisms of cellulose nanocrystals (CNC) (0.1–0.4 %) and CaCl 2 (0.4–1.6 mM) on the solubility of PPI. The results showed that the synergistic effect of CNC (0.3 %) and Ca2+ (1.2 mM) increased the solubility of PPI by 242.31 %. CNC and Ca2+ changed the molecular conformation of PPI, enhanced intermolecular forces, and thus induced changes in the molecular morphology of PPI. Meanwhile, the turbidity of PPI decreased, while surface hydrophobicity, the absolute zeta potential value, viscoelasticity, β-sheet ratio, and thermal properties increased. CNC bound to PPI molecules through van der Waals force and hydrogen bond. Ca2+ could strengthen the crosslinking between CNC and PPI. In summary, it is proposed a valuable combination method to improve the solubility of PPI, and it is believed that this research is of great significance for expanding the application fields of PPI and modifying plant proteins. [Display omitted] [ABSTRACT FROM AUTHOR]

Moisture-induced degradation is an inherent phenomenon at the interface between rubber-modified asphalt and aggregate, moisture ingress through diffusion impairs the integrity of this interface. This study employed molecular simulation to assess the performance of the rubber-modified asphalt and aggregate interface, considering multiple influencing factors such as temperature and loading. Infrared spectroscopy served to validate the alterations in functional groups after moisture exposure. Quantitative metrics, including mean square displacement, interfacial adhesion energy, adsorption energy, radius of gyration, solubility parameter, and molecular orientation, were computed to pinpoint the moisture-induced degradation zones. The findings demonstrated that the maximum moisture diffusion rate subject to various influencing parameters occurred at 298 K and 3 atm, as well as 333 K and 3 atm. Temperature exerted a more profound influence on the rubber-modified asphalt-aggregate interface compared to loading. The strength of hydrogen bonding between moisture and rubber molecules surpassed Van der Waals forces and induction force. Infrared spectroscopy showed that the diffused moisture persisted within the interface. • The moisture-induced degradation zone was successful marked. • The temperature effect on the interface was greater than that of loading. • H-bond force stronger than Van der Waals force and induction force was proposed. [ABSTRACT FROM AUTHOR]

To address the issue of precisely quantifying ship collision risk and identifying collision hotspots in complex waters, this study proposed a regional ship collision risk assessment framework that includes a multi-ship encounter recognition model, a multi-ship comprehensive collision risk assessment model, and a collision hotspot recognition model. Firstly, the directed distance density-based spatial clustering of applications with noise (DBSCAN) algorithm was proposed. Based on this algorithm, a multi-ship encounter recognition model was established to cluster ship positions and obtain ship encounter clusters. Subsequently, the multi-ship comprehensive collision risk assessment model was constructed for multi-ship encounter situations based on the hierarchical classification method, enabling the determination of each ship's Comprehensive Collision Risk Value (CCRV). Finally, the collision hotspot recognition model was built using the grid analysis method, which can identify areas with a higher risk of ship collision. The automatic identification system (AIS) data of the Yangtze River estuary were used to validate the effectiveness of our framework. The results show that our framework can accurately measure ship collisions risks and identify areas with high collision risks, offering valuable insights to maritime authorities, providing actionable insights for real-time ship collision risk monitoring. • A regional ship collision risk assessment framework for multi-ship encounters in complex waters is proposed. • A directed distance DBSCAN algorithm is proposed to identify multiple-ship encounters. • A comprehensive collision risk assessment model suitable for multi-ship encounter situations is presented. • A collision hotspot recognition model is constructed to identify areas with a higher ship collision risk. [ABSTRACT FROM AUTHOR]

The structure of melamine is optimized both at the DFT level with B3LYP and M06-2X functionals using AV T Z basis sets, and at ab initio level using DF-CCSD(T)/V D Z. Predicted planar with DFT when adding the zero-point-energy correction, it is a planar but distorted hexagonal triazine ring with three pyramidal amino groups at the coupled-cluster level. The potential energy surface of melanine is then expected to be rather flat near equilibrium. Both its planarity at the saddle point and non-planarity at equilibrium are deciphered, and pinpointed the role played by the embedded CNH 2 quasi-molecules (tiles). [Display omitted] • Experiment and theory point to a tiny non-planarity of melamine, but no compelling explanation is known. • Its geometry is optimized at DFT (B3LYP and M06-2X functionals, AVTZ basis) and DF-CCSD(T)/VDZ levels. • Planar with DFT when ZPE added, it is a distorted-hexagonal triazine ring with 3 pyramidal amino groups at CC level. • Planarity as a saddle point and non-planarity at equilibrium are deciphered, and pinpointed to the CNH 2 quasi-molec-ules (tiles). • The possibility of tiles being "seen" (playing a key role) is conjectured, and hopefully justified. [ABSTRACT FROM AUTHOR]

The Western High Atlas is one of the most important sectors of the Variscan foldbelt in Morocco and also of its Alpine intracontinental orogen. Its tectonic evolution is thus essential for the understanding, not only of the Moroccan geology, but also of the interaction between successive orogenic cycles which is one of the focus of this article. Furthermore, as the Moroccan Variscides must be seen in the context of the complex dextral collision between Laurasia and Gondwana, this is also a contribution to the comprehension of the complexity of transpressive regimes and strain partitioning processes. New data show that WNW-ESE sinistral Variscan shear zones (mainly the Addouz-Adassil-Anamrou one - AAAsz), although secondary to the main orogenic scale ENE-WSW dextral shear zones, must be considered in order to understand the Late Paleozoic deformation and its Alpine reactivation. In fact, the concentration of the last stages of the Variscan ductile deformation in the steep and irregular AAAsz played an important role in the initiation and localisation of the minor magmatic events and influenced the geometry and kinematics of the Late Variscan WNW-ESE sinistral shear zones. Furthermore, during the Alpine inversion, the orientation of the AAAsz and related major anisotropies tend to be reactivated, with a major reverse component, giving rise to the irregular Adassil-Medinet fault zone, one of the most important structures of the Western High Atlas. • The steep Variscan shear zones control the Atlasic inversion in Western High Atlas • An heterogeneous strike-slip component in pervasive in the Moroccan Variscides • The Variscan shear zones induced strong strain partitioning processes • The overstepping segments of the Variscan shear zones controls the coeval magmatism [ABSTRACT FROM AUTHOR]

• Deep eutectic solvents are screened to remove water and methanol from dimethyl ether. • VLE data are measured to regress the parameters of the NRTL model. • The interaction mechanisms of systems are revealed at the molecular level. • The industrial-scale process of separation has been established and optimized. This study examines the viability of utilizing deep eutectic solvents for the separation of methanol and water from crude dimethyl ether. To begin with, the COSMO-SAC model is employed to screen various deep eutectic solvents, The results indicate that deep eutectic solvents formed by choline chloride as the hydrogen bond acceptor and glycerol as the hydrogen bond donor exhibit excellent selectivity. Additionally, the non-ideal nature of the system is initially assessed using the σ-profile and excess enthalpy. Subsequently, the vapor–liquid equilibrium data for dimethyl ether /methanol/water and deep eutectic solvents are determined through model predictions and saturation vapor pressure experiments. Furthermore, Quantum computation is used to generate the electrostatic potential surfaces and distribution of extremum points of the van der Waals surface of molecules, explaining the interaction sites between molecules. Molecular dynamics simulations are employed to analyze the spatial distribution functions and radial distribution functions of multi-molecular systems. Lastly, a process flow for the removal of methanol and water from dimethyl ether is established. Under the optimal operating conditions, the combined concentration of methanol and water in dimethyl ether is successfully reduced to below 50 ppm, thus demonstrating the feasibility of this approach. [ABSTRACT FROM AUTHOR]

The rotational spectra of two isotopologues have been recorded and interpreted for the van der Waals complex chlorotrifluoroethylene-argon, by using pulsed jet Fourier transform microwave technique. Argon locates out of the ethylene plane, in the FCCF cavity of chlorotrifluoroethylene. The preference of the CFCl side over CF2 can be attributed to the presence of “π-hole” over the double bond in chlorotrifluoroethylene. Non-covalent interaction analysis indicated that the van der Waals interaction occurs between argon and two sites of chlorotrifluoroethylene (the π-system and the F atom of the CFCl top). The steric effect between Ar and the C—Cl bond repulses the Ar atom toward the C—F side. [ABSTRACT FROM AUTHOR]

When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d′f,3p′d), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ). [ABSTRACT FROM AUTHOR]

A theory of exciton quasimolecules (formed from spatially separated electrons and holes) in a nanosystem consisting of double quantum dots (QDs) of germanium synthesized in a silicon matrix is presented. It is shown that the binding energy of the singlet ground state of the quasimolecule of an exciton is considerably larger than the binding energy of biexciton in a silicon single crystal by almost two orders of magnitude. It is shown that the exciton quasimolecule formation is of the threshold character and possible in a nanosystem, where D is the distance between the surfaces of QD that satisfies the following condition: (1) (2) DC C1 D D (where (1) DC and (2) DC are some critical distances). Using the variational method, we obtain the binding energy of the exciton quasimolecule singlet ground state of the system as a function of the distance between the surfaces of QD D, and the QD radius a. It is shown that the convergence of two QDs up to a certain critical value of the distance between the surfaces of QD DC leads to the effective overlapping of the electron wave functions and the appearance of exchange interactions. As a result, the exciton quasimolecules can be formed from the QDs. It is shown that the existence of such a critical distance DC arises from the quantum size effects. Dimensional quantization of electrons and holes motion leads to the following fact: as the distance between the surfaces of the QD DC decreases, the decrease in the energies of interaction of the electrons and holes entering into the Hamiltonian of the exciton quasimolecule cannot compensate for the increase in the kinetic energy of the electrons and holes. At larger values of the distance between the surfaces of the QD D, (2) D2 DC, the exciton quasimolecule breaks down into two excitons (consisting of spatially separated electrons and holes), localized over the QD surfaces. The fact that the energy of the ground state of singlet excitonic quasimolecule is in the infrared range of the spectrum, presumably, allows us to use a quasimolecule for the development of new elements of silicon infrared nanooptoelectronics. [ABSTRACT FROM AUTHOR]

Basic characteristics of a free-jet supersonic expansion beam are presented along with an estimation of a number of expanding CdAr and ZnAr molecules that are excited in the free-jet in the optical–optical double resonance process. The estimation is demonstrated for laser excitation from the ground, via respective A30+(53P1) or C11(41P1) intermediate, to the E31(63S1) or 11(41D2) Rydberg state of CdAr or ZnAr, respectively. A number of subsequently emitted and collected photons is also predicted. [ABSTRACT FROM AUTHOR]

The aim of this study is to acquire a deeper understanding of the response mechanism that is associated with the formation of CdS thin films. We presented an effective and new hybrid sensitisation technique, which involved the 1-step linker between the related chemical bath deposition (CBD) process and the traditional doping method during CBD for synthesising high-quality, CdS thin films. The mechanism for the combined synthesis of the films is also describes. CdS films were electrostatically bonded to soda-lime glass, causing the formation of the intermediate complexes [Cd(NH3)4]2+, which aided in the collision of these complexes with a soda-lime glass slide. In the one-step fabrication technique, 3-Mercaptopropionic Acid (MPA) was employed as a second source of sulphur ions and a linker molecule. Optical studies showed that the bandgap ranged between (2.26–2.52) eV. CdS + MPA films exhibited a uniform distribution of spherical molecules based on their morphological properties. After annealing, this approach significantly altered the electrical characteristics of CdS films. The CdS + MPA films displayed the highest carrier concentration whereas the CdS + Ag + MPA films exhibited the lowest resistivity, with a jump of 3 orders of magnitude. [ABSTRACT FROM AUTHOR]

In this study, we aimed to increase the knowledge regarding the response mechanisms which were associated with the formation of CdS thin films. CdS thin film remains the most appealing alternative for many researchers, as it has been a capable buffer material for effect in film based polycrystalline solar cells (CdTe, CIGSe, CZTS). The Linker Assisted and Chemical Bath Deposition (LA-CBD) technique, which combines the Linker Assisted (LA) technique and the chemical bath deposition (CBD) method for forming high quality CdS thin film, was presented as an efficient and novel hybrid sensitization technique. CdS films were bound to soda lime with the help of electrostatic forces, which led to the formation of the intermediate complexes [Cd (NH3)4]2+ that helped in the collision of these complexes with a soda lime slide. Salvia dye and as a linker molecule 3-Mercaptopropionic acid (MPA) was used in the one step fabrication technique. Optical results showed that the bandgap varied in the range of (2.50 to 2.17) eV. Morphological properties showed a homogeneous distribution of the particles that aspherical in shape in the CdS + MPA + Salvia dye films. This technique significantly affected on the electrical characterizations of CdS films after the annealing process. The CdS + Ag + MPA + Salvia dye films showed the maximum carrier concentration and minimum resistivity, as 5.64 × 10 18 cm−3 and 0.83 Ω cm respectively. [ABSTRACT FROM AUTHOR]

Three-body recombination, or ternary association, is a termolecular reaction in which three particles collide, forming a bound state between two, whereas the third escapes freely. Three-body recombination reactions play a significant role in many systems relevant to physics and chemistry. In particular, they are relevant in cold and ultracold chemistry, quantum gases, astrochemistry, atmospheric physics, physical chemistry, and plasma physics. As a result, three-body recombination has been the subject of extensive work during the last 50 years, although primarily from an experimental perspective. Indeed, a general theory for three-body recombination remains elusive despite the available experimental information. Our group recently developed a direct approach based on classical trajectory calculations in hyperspherical coordinates for three-body recombination to amend this situation, leading to a first principle explanation of ion-atom-atom and atom-atom-atom three-body recombination processes. This review aims to summarise our findings on three-body recombination reactions and identify the remaining challenges in the field. [ABSTRACT FROM AUTHOR]

Perturbation by a neighboring molecule M appreciably alters the properties of both the ground and excited states of molecular oxygen, as reflected in a variety of photophysical phenomena. In this article, we build upon the ~ 100 year history of work in this field, illustrating how the M–O2 system continues to challenge the scientific community, facilitating better insight into fundamental tenets of chemistry and physics. [ABSTRACT FROM AUTHOR]

In this study, four new piperazinium salts, namely, 4-phenylpiperazin-1-ium 4- ethoxybenzoate monohydrate, C9H9O3⋅C10H15N2⋅H2O (I); 4-phenylpiperazin-1-ium 4-methoxybenzoate monohydrate, C10H15N2⋅C8H7O3⋅H2O (II); 4-phenylpiperazin-1-ium 4-methylbenzoate monohydrate, C10H15N2⋅C8H7O2⋅H2O (III); and 4-phenylpiperazin-1-ium trifluoroacetate 0.12 hydrate, C10H15N2⋅C2F3O2⋅-0.12H2O (IV), have been synthesized. The single-crystal structures of these compounds reveal that all of them crystallize in the triclinic P1 space group and the crystal packing of (I)--(III) is built up of ribbons formed by a combination of hydrogen bonds of type N--H⋯O, O--H⋯O and other weak interactions of type C--H⋯O and C--H⋯, leading to a three-dimensional network. In the crystal of (IV), the cations and the anions are connected by C--H⋯O, N--H⋯O and C--H⋯F hydrogen bonds and by C--H⋯ interactions, forming sheets which in turn interact to maintain the crystal structure by linking through the oxygen atoms of water molecules and van der Waals interactions, giving the whole structure. [ABSTRACT FROM AUTHOR]

Carrier particle spray freeze-drying is a new technology with high added value for thermosensitive powder spray freeze-drying. The technology includes the following steps: atomization, coating, freezing, and drying. Due to the action of carrier particles, the condensation of frozen droplets in the conventional spray freeze-drying process is overcome. However, there are many influencing factors involved in the process of freezing coating. The mechanism of the complex droplet collision freezing process still needs to be studied. In this paper, from the perspective of spray freezing coating after atomized droplets collide with low-temperature carrier particles, the coating process and freezing process of single droplets impacting the sphere are analyzed microscopically. The freezing coating processes of static and dynamic carrier particles are reviewed. Moreover, the surface evaluation of powder and equipment development for creating powder products is discussed. [ABSTRACT FROM AUTHOR]

The review covers the dynamics of different kinds of one electron Rydberg quasimolecules in various environments, such as being subjected to electric and/or magnetic fields or to a plasma environment. The higher than geometrical symmetry of these systems is due to the existence of an additional conserved quantity: the projection of the supergeneralized Runge–Lenz vector on the internuclear axis. The review emphasizes the fundamental and practical importance of the results concerning the dynamics of these systems. [ABSTRACT FROM AUTHOR]

• New 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals analysis. • The Hirshfeld surface analysis was employed to examine intermolecular contacts. • Compare the spectral studies of DFT experimental and theoretical and vibrational energy distribution analysis (VEDA) analysis. • Anti-HIV activities were observed for synthesized compounds. • FDA-approved anti-HIV drug of Nelfinavir molecular docking and ADME (Computational study) have been predicted. The 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals were grown by slow evaporation method and the structure is confirmed through FT-IR, 1H NMR, and 13C NMR spectral analyses. Single crystal X-ray diffraction revealed that the title compound having chair conformation of the piperidine ring, with an axial orientation of phenyl rings at C-2 and C-6 positions and an isopropyl group at C-3. Hirshfeld surface analysis was employed to examine intermolecular contacts and strong and weak attractive, repulsive, and van der Waals interactions in the molecule were determined using the reduced density gradient method (RDG). The geometrical parameters obtained through Density Functional Theory are compared with experimental values and also conducted to optimize structural parameters, frontier molecular orbitals (FMOs), and molecular electrostatic potential surface analysis (MEPS). NBO calculations were employed to investigate intermolecular and intramolecular charge movement, as well as the molecule's stability. Vibrational Energy Distribution Analysis (VEDA) software facilitated potential energy decomposition (PED) analysis using FT-IR wave numbers. The title compound molecular docking data were compared with the markedly available FDA-approved anti-HIV drug of Nelfinavir and their results were discussed, ADME analysis studies were discussed concerning FDA-approved anti-HIV drugs, including Nelfinavir, Betulinic Acid, Haloperidol, and Donepezil. [Display omitted] [ABSTRACT FROM AUTHOR]

We propose a physically motivated decomposition of density functional theory (DFT) 3-body nonadditive interaction energies into the exchange and density-deformation (polarization) components. The exchange component represents the effect of the Pauli exclusion in the wave function of the trimer and is found to be challenging for density functional approximations (DFAs). The remaining densitydeformation nonadditivity is less dependent upon the DFAs. Numerical demonstration is carried out for rare gas atom trimers, Ar2-HX (X = F, Cl) complexes, and small hydrogen-bonded and van derWaals molecular systems. None of the tested semilocal, hybrid, and range-separated DFAs properly accounts for the nonadditive exchange in dispersion-bonded trimers. By contrast, for hydrogen-bonded systems, range-separated DFAs achieve a qualitative agreement to within 20% of the reference exchange energy. A reliable performance for all systems is obtained only when the monomers interact through the Hartree-Fock potential in the dispersion-free Pauli blockade scheme. Additionally, we identify the nonadditive second-order exchange-dispersion energy as an important but overlooked contribution in force-field-like dispersion corrections. Our results suggest that range-separated functionals do not include this component, although semilocal and global hybrid DFAs appear to imitate it in the short range. [ABSTRACT FROM AUTHOR]

Two hybrid van der Waals density functionals (vdW-DFs) are developed using 25% Fock exchange with (i) the consistent-exchangevdW-DF-cx functional [K. Berland and P. Hyldgaard, Phys. Rev.B89, 035412 (2014)] and (ii) with the vdW-DF2 functional [K. Lee et al., Phys. Rev. B 82, 081101 (2010)]. The ability to describe covalent and non-covalent binding properties of molecules is assessed. For properties related to covalent binding, atomization energies (G2-1 set), molecular reaction energies (G2RC set), and ionization energies (G21IP set) are benchmarked against experimental reference values. We find that hybrid-vdW-DF-cx yields results that are rather similar to those of the standard non-empirical hybrid PBE0 [C. Adamo and V. Barone, J. Chem. Phys. 110, 6158 (1999)], with mean average deviations (MADs) of 4.9 and 5.0 kcal/mol for the G2-1 set, respectively. In this comparison, experimental reference values are used, back corrected by wavefunction-based quantum-chemistry calculations of zero-point energies. Hybrid vdW-DF2 follows somewhat different trends, showing on average significantly larger deviations from the reference energies, with a MAD of 14.5 kcal/mol for the G2-1 set. Non-covalent binding properties of molecules are assessed using the S22 benchmark set of non-covalently bonded dimers and the X40 set of dimers of small halogenated molecules, using wavefunction-based quantum chemistry results as references. For the S22 set, hybrid-vdW-DFcx performs better than standard vdW-DF-cx for the mostly hydrogen-bonded systems, with MAD dropping from 0.6 to 0.3 kcal/mol, but worse for purely dispersion-bonded systems, with MAD increasing from 0.2 to 0.6 kcal/mol. Hybrid-vdW-DF2 offers a slight improvement over standard vdW-DF2. Similar trends are found for the X40 set, with hybrid-vdW-DF-cx performing particularly well for binding energies involving the strongly polar hydrogen halides, but poorly for systems with tiny binding energies. Our study of the X40 set reveals the potential of mixing Fock exchange with vdW-DF, but also highlights shortcomings of the hybrids constructed here. The solid performance of hybrid-vdW-DF-cx for covalent-bonded systems, as well as the strengths and issues uncovered for non-covalently bonded systems, makes this study a good starting point for developing even more accurate hybrid vdW-DFs. [ABSTRACT FROM AUTHOR]

In this work, a range of van der Waals type density functionals are applied to the H2O/NaCl(001) and H2O/MgO(001) interface systems to explore the effect of an explicit dispersion treatment. The functionals we use are the self-consistent vdW functionalsvdW-DF,vdW-DF2, optPBE-vdW, optB88- vdW, optB86b-vdW, and vdW-DF-cx, as well as the dispersion-corrected PBE-TS and PBE-D2 methods; they are all compared with the standard PBE functional. For both NaCl(001) and MgO(001), we find that the dispersion-flavoured functionals stabilize thewater-surface interface by approximately 20%-40% compared to the PBE results. For NaCl(001), where the water molecules remain intact for all overlayers, the dominant contribution to the adsorption energy from "density functional theory dispersion" stems from the water-surface interactions rather than the water-water interactions. The optPBE-vdW and vdW-DF-cx functionals yield adsorption energies in good agreement with available experimental values for both NaCl and MgO. To probe the strengths of the perturbations of the adsorbed water molecules, we also calculated water dipole moments and found an increase up to 85% for water at the MgO(001) surface and 70% at the NaCl(001) surface, compared to the gas-phase dipole moment. [ABSTRACT FROM AUTHOR]

We use accurate quantum scattering calculations to elucidate the role of short-range molecule-field interactions in atom-molecule inelastic collisions and abstraction chemical reactions at low temperatures. We consider two examples: elastic and inelastic scattering of NH(3Σ) molecules with Mg(1S) atoms in a magnetic field; reactive scattering LiF + H→Li + HF in an electric field. Our calculations suggest that, for non-reactive collision systems and abstraction chemical reactions, the molecule-field interactions cannot generally be neglected at short range because the atom-molecule potential passes through zero at short range. An important exception occurs for Zeeman transitions in atom-molecule collisions at magnetic fields ≲1000 G, for which the molecule-field couplings need only be included at large ρ outside the range of the atom-molecule interaction. Our results highlight the importance of an accurate description of ρ-dependent molecule-field interactions in quantum scattering calculations on molecular collisions and chemical reactions at low temperatures. [ABSTRACT FROM AUTHOR]

Freeway crashes occupied 30% of total crashes. The advanced driver-assistance system (ADAS) often underestimates or omits the necessary collision warning. To investigate the forward collision in complex traffic conditions, the TTC (time-to-collision) is regarded as a surrogate for collision risk assessment. The study aims to design a forward-collision warning method for ADAS in the urban freeway scenario. The testing vehicle is equipped with sensors and a satellite navigation system. The TTC was collected from the Xi'an Rao Cheng expressway for the car-following scenario for three days. A comprehensive Gaussian model, which consists of three sub-GMM models is applied to describe the TTC distribution. The vehicle trajectories were extracted in the car-following state. To improve the efficiency of the forwarding collision system, four seconds are chosen as an analysis window in the car-following state. Two time-series machine models were used to predict TTC in advance. The TTC prediction models were constructed on the basis of the long short-term memory (LSTM). The prediction result was compared with the deep belief network (DBN) model. The comparison results show that the LSTM model is faster than the DBN model. The number of iterations is 100. The loss function of the LSTM is 0.06. The LSTM outperforms the DBN model and is suitable for car-following warnings. [ABSTRACT FROM AUTHOR]

As one of the important physical models, the variable-coefficient breaking soliton model describes the dynamics of solitary waves and Riemann waves in hydrodynamics. Applying the two function approach into the variable-coefficient breaking soliton model, we find an exponential-form variable separation solution with two arbitrary functions, which covers many hyperbolic and trigonometric function solutions. Based on this solution and choosing suitably two arbitrary functions, complex waves including dromion pair and single dromion superposed on a line soliton background and their collisions between complex waves and between dromion and periodic wave are discussed. For the complex waves such as the dromion pair and single dromion superposed on a line soliton background and their collisions between complex waves, two components of this model possess both striking physical meanings. However, for the collision between dromion and periodic wave, one component of this model has unique physical meaning, yet the other component of the same model appears the singularity structure. Therefore, when one discusses complex waves and their collisions for one component of the model, one must take care of non-physical structures for another component of the same model lest one arbitrarily claims that he finds the so-called novel localized structures, which are actually false non-physical structures. [ABSTRACT FROM AUTHOR]

We investigated ion‐beam (IB)‐treated polyacrylamide (PAM) film as a liquid crystal (LC) alignment layer. Polarized optical microscopy and pretilt angle analysis show the uniform LC alignment status. Atomic force microscopy shows the IB etching effect, and X‐ray photoelectron spectroscopy indicates the formation of carbon–oxygen bonds on the surface, which ensured the uniform alignment of LC molecules via van der Waals forces interaction. The reformed PAM films also had good thermal budgets and optical transparency for the LC system. The IB‐treated PAM films demonstrated stable electro‐optical performances in a twisted nematic LC system. Hence, IB treatment can be an effective method to apply several polymer materials to the LC alignment layer, and IB‐irradiated PAM films have remarkable potential for use in the LC system. [ABSTRACT FROM AUTHOR]

On the basis of examples like this, mathematicians (or mathematics students reading the textbook example) might expect that facts about complex numbers oftentimes reveal the reasons for results exclusively concerning real numbers - results that would otherwise have seemed coincidental. Imaginary coordinates for points of intersection arise when there is no Euclidean triangle with sides of lengths I r i SB 1 sb , I r i SB 2 sb , and I L i , which occurs when I L i > I r i SB 1 sb + I r i SB 2 sb (case (b) in the figure) or I L i < | I r i SB 1 sb HT ht I r i SB 2 sb | (case (c) in the figure). [Extracted from the article]

The first derivatives of the electronic moments of the transition along the coordinates, HT ht , were calculated numerically. For this, the Dirac distribution function I i in Eq. (1) is replaced by expression HT ht . Therefore, in practice, the Taylor series is used near the equilibrium geometry of the ground electronic state: HT ht Graph (2)where B I Q i b are mass-weighted normal coordinates. [Extracted from the article]

In this research, a dataset including 206 volatile organic compounds was used to develop quantitative structure–retention relationship models for predicting the retention indices of volatile organic compounds on DB-5 stationary phase. A total of 141 molecules were put in train set to build models and 65 molecules were put in test set to validate models, externally. By using stepwise-multiple linear regression, two descriptors including X1sol (solvation connectivity index chi-1) and AAC (mean information index on atomic composition) were selected to create linear and nonlinear quantitative structure–retention relationship models. Multiple linear regression, epsilon-support vector regression and deep learning-based artificial neural network were used as modeling techniques. All models were validated by calculating several statistical parameters for both train and test sets that show created models have high predictive power. R2 values for the test set of multiple linear regression, epsilon-support vector regression and deep learning-based artificial neural network models were 0.90, 0.94 and 0.94, respectively. Results show the Van der Waals interactions of molecules with methyl groups in DB-5 stationary phase and the electrostatic interactions of atoms with partial negative charge in molecules with the hydrogen atoms of phenyl groups in DB-5 stationary phase are responsible for the separation of volatile organic compounds in DB-5 stationary phase. Finally, these created models were used to predict the retention indices of 694 volatile organic compounds that had no retention index data on DB-5 stationary phase. [ABSTRACT FROM AUTHOR]

Throughout, Tahmahkera weaves in moments and wisdom captured in tribal film and video in moving-image oral histories and interviews with knowledge keepers and Comanche elders. I Mar i u I awe i establishes a storytelling practice of call and response that Tahmahkera brilliantly adapts to the project of answering, talking back to, and counter-narrating media representations of indigeneity in general and of Comanches in particular. Elsewhere, Tahmahkera incisively analyzes the casting and performance of Johnny Depp as Tonto and the creation of a more fully-rounded Comanche backstory for that character in Gore Verbinski's 2013 I The Lone Ranger i . [Extracted from the article]

In order to prevent collision of complex structure well, accurate measurement of the distance of adjacent wells must be required during the development of the unconventional reservoir. The precision of the traditional survey tools and scanning software is not accurate enough. Based on the electromagnetic anticollision measuring calculation method, the electromagnetic anticollision detection tool was designed and simulation experiments were carried out. The influence of different position relations between sensor and casing on magnetic field strength detected by the sensor was analyzed. When the sensor and the casing were parallel and the distance of them was 0.5 m∼3 m, the tool could calculate accurately the distance and orientation of the adjoining well. When the angle between the sensor and the casing was within 50°, the calculation result was accurate. This research result validated the accuracy of the principle of the electromagnetic anticollision tool while drilling cluster well, and it could provide theoretical support for the development of electromagnetic detection tools. [ABSTRACT FROM AUTHOR]

Maritime collision accidents occur frequently and result in huge damages. Complex collision accidents are especially associated with worse damages. Complex maritime collision accidents involve other types of accidents barring the main accident, such as fire, explosions, capsizes, sinking, and even casualties. When a maritime accident occurs, the maritime accident verdict covers the surveyed facts from the origin of the accident to the consequences. The survey usually reveals the primary cause of the accident; however, complex causes may remain latent. Therefore, this research aims to apply text analytics to maritime verdicts of collision accident cases to identify the latent causes in complex collision accidents. The proposed methods separated the collected corpus into the training dataset and the test dataset. The word propensity database was extracted from the training dataset and applied to sample verdicts of complex maritime collision accidents in the test dataset. The expected results of this research were words that appeared in only complex maritime accidents with a high propensity for additional categories and the relevant context that explains the latent causes that underlie the complexity of the maritime accident. The conclusion suggested that the latent causes derived should be provided to ships to help prevent future complex collision accidents. [ABSTRACT FROM AUTHOR]

In the last decade several papers have announced usefulness of two-dimensional materials for high operating temperature photodetectors covering long wavelength infrared spectral region. Transition metal dichalcogenide photodetectors, such as PdSe2/MoS2 and WS2/HfS2 heterojunctions, have been shown to achieve record detectivities at room temperature (higher than HgCdTe photodiodes). Under these circumstances, it is reasonable to consider the advantages and disadvantages of two-dimensional materials for infrared detection. This review attempts to answer the question thus posed. [ABSTRACT FROM AUTHOR]

Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively characterised, line degeneracies of surface states are not well understood. We show that SnIP, a quasi-one-dimensional van der Waals material with a double helix crystal structure, exhibits topological nodal rings/lines in both the bulk phonon modes and their corresponding surface states. Using a combination of first-principles calculations, symmetry-based indicator theories and Zak phase analysis, we find that two neighbouring bulk nodal rings form doubly degenerate lines in their drumhead-like surface states, which are protected by the combination of time-reversal symmetry T and glide mirror symmetry M ¯ y . Our results indicate that surface degeneracies can be generically protected by symmetries such as T M ¯ y , and phonons provide an ideal platform to explore such degeneracies. [ABSTRACT FROM AUTHOR]