The European Physical Journal D最新文献

Ethylene glycol (EG) is widely applied in various fields. However, it is toxic and poses hazards to human health and the environment. This study employed density functional theory (DFT) with the B3LYP/6-31G + (d, p) basis set to investigate the physicochemical properties of the EG molecule under external electric fields. Key properties analyzed include total energy, bond lengths, dipole moment, infrared (IR) spectra, tunneling effects, Raman spectra and UV–vis (Ultraviolet–Visible) spectra. Furthermore, the degradation of EG under electric fields was studied based on potential energy curves. The research reveals the mechanisms governing the effects of external electric fields on EG’s structure, spectral characteristics, and dissociation pathways, providing a theoretical basis for EG pollution control.

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The resonant transfer and excitation plus X-ray emission (RTEX) process are studied systematically for H-like and He-like ions in the impulse approximation. The detailed RTEX cross sections are presented for 14 elements, including C, N, O, Ar, Ca, Fe, Cu, Kr, Mo, Sn, Cs, Au, Bi, and U colliding with H₂, H₂O, and Ar targets. The calculated results agree well with both available experimental and other theoretical values, except for Ca¹⁹⁺  + H₂ collisions, in which a significant discrepancy between the experiments is observed. The RTEX cross sections of H-like ions are found decreasing with increasing of the nuclear charge Z. Similar variation trend of cross sections as the case of H-like ions are observed for high-Z He-like ions, while for low-Z He-like C⁴⁺, N⁵⁺, and O⁶⁺ ions, the RTEX cross sections increase with increasing nuclear charge Z. The electron momentum distribution (Compton profile) of targets are found significantly influencing the RTEX cross sections, for the same projectile ion colliding with H₂, H₂O, and Ar targets, respectively, the cross sections σ_Ar > σ(text{H}_2text{O} ) > σ(text{H}_2) are shown for dominant resonant peaks.

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The RTEX cross sections for He-like Ca¹⁸⁺, Fe²⁴⁺, U⁹⁰⁺ ions colliding with H₂ target,and compared with the available experimental and theoretical results [15-18, 43]. The blue vertical bars indicate the DR resonance positions and strengths.

The energy levels, electric dipole transition rates and wavelengths of Cu-like (Au⁵⁰⁺) and Zn-like (Au⁴⁹⁺) ions were systematically calculated using the multi-configuration Dirac–Hartree–Fock method. The calculations incorporated electron correlation effects between valence-valence, core-valence, and core-core electrons. It was found that electron correlation significantly impacts the excitation energies of the Au⁵⁰⁺ and Au⁴⁹⁺ ions. In the calculation, the electron correlation configurations are expanded to n = 8 for the Au⁵⁰⁺ ion and n = 7 for the Au⁴⁹⁺ ion through single and double substitutions, resulting in good convergence for the excitation energy. Additionally, QED effects, Breit interaction, and the finite-nuclear-size effects to the excited states of Au⁵⁰⁺ and Au⁴⁹⁺ ions are also considered in the calculation. QED effects and the Breit interaction, in particular, were found to have an important influence for the excitation energy. Moreover, the calculated transition energies are in excellent agreement with experimental data, with a deviation of less than 0.078%. These results are expected to be useful for diagnosing high-temperature gold plasmas, particularly in fusion plasma applications.

Graphical Abstract

The calculated transition energies 4s 4p for the Au⁵⁰⁺ ion under different models and compared to experimental data.

This study presents detailed analysis of theoretical atomic spectra of various argon (Ar) ions, specifically F-like, O-, N-, and C-like Ar ions, calculated using a method implemented in the flexible atomic code, which combines the relativistic configuration interaction method with many-body perturbation theory (FAC-MBPT). Radiative transition rates and oscillator strengths were calculated in terms of length and velocity forms which highlights the accuracy of the calculated data. A collisional-radiative model was developed to calculate theoretical spectra for optically allowed transitions of the four Ar ions. The spectral features and spectral ranges were analyzed and identified. A comparison with available data shows good agreement with the findings. The resulting spectra and the calculated data provide valuable insights for Ar plasma diagnostics and contribute to the understanding of complex astrophysical spectra.

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Isoflurane is a halogenated anaesthetic gas adopted in modern clinical practice due its efficacy and safety profile. However, its atmospheric persistence contributes to global warming potential that influences its overall environmental burden. In this study, we employed a crossed electron-molecular beam technique to investigate dissociative electron attachment (DEA) processes in order to investigate isoflurane fragmentation induced by electron impact. The DEA process results in the formation of twelve anionic fragments, including halogenated anions (Cl⁻ and F⁻), complex fluoro-chloro containing species (e.g., [C₂F₃Cl]⁻, [C₂HFCl]⁻), and oxygen-containing anions such as [CHF₂O]⁻ and [CFO]⁻. The most intense signal corresponds to Cl⁻, which exhibits a sharp resonance near 0.1 eV, can be attributed to a shape resonance or due high dipole moment of isoflurane (2.47 D) to a vibrational Feshbach resonance (VFR). In contrast, F⁻ formation is observed in a high-energy domain (4–7 eV) and proceeds via core-excited resonance. Remarkably, the [FHF]⁻ anion was detected with unexpectedly high intensity at low energies, suggesting the occurrence of complex multi-bond dissociation and electron-induced molecular rearrangement. These findings provide important insights into the electron-induced chemistry of halogenated anaesthetics.

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