The European Physical Journal D最新文献

The mass spectrum (MS) and appearance energies (AEs) of the cationic fragments formed in electron collisions with isobutanol were investigated in this work using a HIDEN EPIC 300 mass spectrometer. We highlight here the discovery of 6 new cationic fragments in the literature for MS as well as 10 AEs and ps values reported for the first time. The MS was acquired for electron impact energy of 70 eV, in the mass region of 1–80 amu and with a resolution of 1 amu. Here we observed the formation of 45 cationic fragments, thus complementing some data previously reported in the literature, 6 of which were unpublished. The relative abundances of the peaks recorded in the MS show good agreement within the experimental error range, with the available values reported in the literature, where such comparison is carried out. The AEs were determined from the acquisition of isobutanol ionic fragmentation curves, for the electron impact energies covering the cationic fragment formation threshold region. The extended Wannier law was applied to obtain the AEs and Wannier exponents (p) of the fragments recorded in the MS, with relative intensity typically greater than 4% of the most intense fragment. This resulted in MS of isobutanol and data for 15 fragments, of which 10 of these fragments are reported for the first time in this work.

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This work elucidates the effects of a short laser pulse on the excitation and ionization dynamics of an endofullerene system trapping He, Ne, and Ar atoms. The interactions of noble gas atoms are simulated within the framework of the Single Active Electron (SAE) approximation, and the encapsulation parameters are analyzed to illustrate the excitation and ionization dynamics. The endohedral confinement is modeled using the Woods–Saxon potential, which is a practical and advantageous model that aligns well with experimental data and considers static encapsulation. By considering different numerical values of the endohedral trapping parameters in simulating encapsulation, a detailed analysis on the depth of confinement, spherical shell thickness, the inner radius, and the smoothing parameters is performed to ferret out encapsulation effects in various forms. By determining the strength range and specific frequency values (and ranges) of the laser pulse, the work interprets how electron dynamics in endohedral fullerenes are shaped under laser pulses. All parameters and their respective ranges are crucial gains for optimizing system performance.

A packed-bed dielectric barrier discharge was used to investigate CO₂ to CO conversion under different operating conditions as frequency, CO₂/Ar gas mixture composition and gas flow rate, to understand the effects of their variations on current–voltage discharge characteristics, CO₂ to CO conversion ratios, CO yields, and ozone production. Using TiO₂-coated glass beads has changed the discharge behavior from the glow mode to a combined filamentary and surface discharge mode, making the discharge more diffuse for higher frequencies in the range of 3.6 to 6 kHz. Higher CO₂ to CO conversion and CO yield are achieved by lowering both operating frequencies and CO₂ concentrations in CO₂/Ar gas mixture. For TiO₂-coated glass beads packed discharge, increasing discharge frequency from 3.6 to 6 kHz lower CO₂ conversion from 11.2% to 2.5%, while increasing CO₂ concentrations in CO₂/Ar gas mixture from 10 to 40% lowers conversion from 11.2% to 5%. The enhancement of ozone production by the introduction of TiO₂-coated glass beads packing material may be related to improvements of conversion ratio from CO₂ to CO and CO yield showing their larger values at lower frequencies and lower CO₂ percentages in CO₂/Ar gas mixture. Using inexpensive and easily synthesized in large quantities catalyst material, realized by TiO₂ coating of glass beads in a microwave plasma torch, has permitted to reach DBD operational modes adequate for CO production in moderate concentrations suitable for applications in medicine and agriculture.

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The positron and electron impact ionization of argon 3p at 200 eV impact energy is investigated using a theoretical model called 3CWZ. Within this model all particles of the continuum are represented by Coulomb waves with variable charges Z(r), the post-collision interaction and exchange effects are also included. The triple differential cross section is calculated and compared with recent measurements of Dubois and de Lucio (Atoms 9:78, 2021) and other theories when available, for several kinematics. Our numerical results are in overall good agreement with experiments and illustrate projectile charge effects, better than other available theories.

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Lonization of argon atom by positron and electron impact

In this study, we investigated the electrical and thermoelectric properties of the zinc porphyrin dimer and the double-dimer zinc porphyrin molecular junctions using density functional theory (DFT) combined with the non-equilibrium Green’s function method. Our results demonstrate that the electronic transport and thermoelectric properties of these junctions can be significantly improved in the presence of another dimer. By adding a new zinc porphyrin dimer, the electrical conductance (G) increased up to an order of magnitude and showed further enhancement in the Seebeck coefficient for a good range of Fermi energies. However, the situation is the opposite in the case of the structure of zinc porphyrin dimer without any additives. These results imply that through modifications in the molecular configuration, there exists a promising potential for enhancing the figure of merit (ZT) value, thereby these systems can be potentially utilized to increase the opportunities for versus application in molecular-scale thermoelectric energy generators we conducted a comparative analysis between the zinc porphyrin dimer and the double-dimer zinc porphyrin molecular junctions.

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Zinc porphyrin dimers-based molecular wire

In recent years, there has been a growing global interest in ultra-wide bandgap semiconductor materials, with aluminium nitride emerging as a particularly promising material. Using density-functional theory (DFT) at the CAM-B3LYP/6-311G(3d,2p) basis set level, we have systematically optimized the geometries of the (AlN)₁₂ cluster. Furthermore, the structural and thermodynamic changes of these clusters under the external electric field (EEF) were investigated. When the external electric field intensity increased the energy gap decreases continuously, infrared spectral analysis showed an obvious Stark effect, and the molecular structure showed significant alterations. Additionally, the study examined orbital compositions and excitation properties of twenty excited states using time-dependent density-functional theory (TD-DFT). The results indicated a decrease in excitation energy with increasing EEF, resulting in longer wavelengths and red-shifted spectral. These findings provide an opportunity to precisely modulate the electronic properties of (AlN)₁₂ cluster by controlling the strength and direction of the EEF, opening up more possibilities for their application in photoelectronic devices.

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