Journal Description
Atoms
Atoms
is an international, peer-reviewed and cross-disciplinary scholarly journal of scientific studies related to all aspects of the atom published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Astrophysics Data System, Inspec, CAPlus / SciFinder, INSPIRE, and other databases.
- Journal Rank: CiteScore - Q2 (Nuclear and High Energy Physics)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 19.6 days after submission; acceptance to publication is undertaken in 3.8 days (median values for papers published in this journal in the first half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
1.8 (2022);
5-Year Impact Factor:
1.8 (2022)
Latest Articles
Bose Polaron in a One-Dimensional Lattice with Power-Law Hopping
Atoms 2023, 11(8), 110; https://doi.org/10.3390/atoms11080110 - 06 Aug 2023
Abstract
Polarons, quasiparticles resulting from the interaction between an impurity and the collective excitations of a medium, play a fundamental role in physics, mainly because they represent an essential building block for understanding more complex many-body phenomena. In this manuscript, we study the spectral
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Polarons, quasiparticles resulting from the interaction between an impurity and the collective excitations of a medium, play a fundamental role in physics, mainly because they represent an essential building block for understanding more complex many-body phenomena. In this manuscript, we study the spectral properties of a single impurity mixed with identical bosons in a one-dimensional lattice with power-law hopping. In particular, based on the so-called T-matrix approximation, we show the existence of well-defined quasiparticle branches for several tunneling ranges and for both repulsive and attractive impurity-boson interactions. Furthermore, we demonstrate the persistence of the attractive polaron branch when the impurity-boson bound state is absorbed into the two-body continuum and that the attractive polaron becomes more robust as the range of the hopping increases. The results discussed here are relevant for the understanding of the equilibrium properties of quantum systems with power-law interactions.
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(This article belongs to the Special Issue Recent Trends on Quantum Fluctuations in Ultra-Cold Quantum Gases)
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Decay of Persistent Currents in Annular Atomic Superfluids
Atoms 2023, 11(8), 109; https://doi.org/10.3390/atoms11080109 - 27 Jul 2023
Abstract
We investigate the role of vortices in the decay of persistent current states of annular atomic superfluids by solving numerically the Gross–Pitaevskii equation, and we directly compare our results with the Li experiment at LENS data. We theoretically model the optical phase-imprinting
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We investigate the role of vortices in the decay of persistent current states of annular atomic superfluids by solving numerically the Gross–Pitaevskii equation, and we directly compare our results with the Li experiment at LENS data. We theoretically model the optical phase-imprinting technique employed to experimentally excite finite-circulation states in the Bose–Einstein condensation regime, accounting for imperfections of the optical gradient imprinting profile. By comparing simulations of this realistic protocol to an ideal imprinting, we show that the introduced density excitations arising from imperfect imprinting are mainly responsible for limiting the maximum reachable winding number in the superfluid ring. We also investigate the effect of a point-like obstacle with variable potential height on the decay of circulating supercurrents. For a given obstacle height, a critical circulation exists, such that for an initial circulation larger than the supercurrent decays through the emission of vortices, which cross the superflow and thus induce phase slippage. Higher values of the obstacle height further favor the entrance of vortices, thus leading to lower values of . Furthermore, the stronger vortex-defect interaction at higher leads to vortices that propagate closer to the center of the ring condensate. The combination of both these effects leads to an increase in the supercurrent decay rate for increasing , in agreement with experimental observations.
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(This article belongs to the Special Issue Recent Trends on Quantum Fluctuations in Ultra-Cold Quantum Gases)
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Open AccessArticle
Setup for the Ionic Lifetime Measurement of the 229mTh3+ Nuclear Clock Isomer
by
, , , , , , , , , and
Atoms 2023, 11(7), 108; https://doi.org/10.3390/atoms11070108 - 24 Jul 2023
Abstract
For the realization of an optical nuclear clock, the first isomeric excited state of thorium-229 (229mTh) is currently the only candidate due to its exceptionally low-lying excitation energy ( eV). Such a nuclear clock holds promise not only
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For the realization of an optical nuclear clock, the first isomeric excited state of thorium-229 (229mTh) is currently the only candidate due to its exceptionally low-lying excitation energy ( eV). Such a nuclear clock holds promise not only to be a very precise metrological device but also to extend the knowledge of fundamental physics studies, such as dark matter research or variations in fundamental constants. Considerable progress was achieved in recent years in characterizing 229mTh from its first direct identification in 2016 to the only recent observation of the long-sought-after radiative decay channel. So far, nuclear resonance as the crucial parameter of a nuclear frequency standard has not yet been determined with laser-spectroscopic precision. To determine another yet unknown basic property of the thorium isomer and to further specify the linewidth of its ground-state transition, a measurement of the ionic lifetime of the isomer is in preparation. Theory and experimental investigations predict the lifetime to be 103–104 s. To precisely target this property using hyperfine structure spectroscopy, an experimental setup is currently being commissioned at LMU Munich. It is based on a cryogenic Paul trap providing long-enough storage times for 229mTh ions, that will be sympathetically cooled with 88Sr+. This article presents a concept for an ionic lifetime measurement and discusses the laser-optical part of a setup specifically developed for this purpose.
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(This article belongs to the Special Issue Over a Century of Nuclear Isomers: Challenges and Prospects)
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Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition
Atoms 2023, 11(7), 107; https://doi.org/10.3390/atoms11070107 - 22 Jul 2023
Abstract
The exponentially correlated Hylleraas–configuration interaction method (E-Hy-CI) is a generalization of the Hylleraas–configuration interaction method (Hy-CI) in which the single of an Hy-CI wave function is generalized to a form of the generic type
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The exponentially correlated Hylleraas–configuration interaction method (E-Hy-CI) is a generalization of the Hylleraas–configuration interaction method (Hy-CI) in which the single of an Hy-CI wave function is generalized to a form of the generic type . This work continues the exploration, begun in the first two papers in this series (on the helium atom and on ground and excited states of Li II), of whether wave functions containing both linear and exponential factors converge more rapidly than either one alone. In the present study, we examined not only 1 states but 1s2p states for the He I, Li II, Be III, C V and O VII members of the He isoelectronic sequence as well. All energies except He I are better than previous results. The wave functions obtained were used to calculate oscillator strengths, including upper and lower bounds, for the He-sequence lowest (resonance) transition. Interpolation techniques were used to make a graphical study of the oscillator strength behavior along the isoelectronic sequence. Comparisons were made with previous experimental and theoretical results. The results of this study are oscillator strengths for the 1 1s2 He isoelectronic sequence with rigorous non-relativistic quantum mechanical upper and lower bounds of (0.001–0.003)% and probable precision ≤ 0.0000003, and were obtained by extending the previously developed E-Hy-CI formalism to include the calculation of transition moments (oscillator strengths).
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(This article belongs to the Special Issue Recent Advances in Atomic and Molecular Spectroscopy)
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Towards Understanding Incomplete Fusion Reactions at Low Beam Energies: Modified Sum Rule Model
by
and
Atoms 2023, 11(7), 106; https://doi.org/10.3390/atoms11070106 - 21 Jul 2023
Abstract
We investigated the enhanced production of nuclei formed via incomplete fusion (ICF) reactions near and above the Coulomb barrier energies (5–8 MeV/A). The cross-sections of the evaporation residues formed in the reactions— B+ Sn, B+ Sn and B+
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We investigated the enhanced production of nuclei formed via incomplete fusion (ICF) reactions near and above the Coulomb barrier energies (5–8 MeV/A). The cross-sections of the evaporation residues formed in the reactions— B+ Sn, B+ Sn and B+ Sn—were measured using off-line gamma-ray spectrometry. The sum rule model (SRM) by Wilczyński et al. predicted the cross-section values too low compared to our experimental results. In earlier studies, the same model has been very successful in explaining ICF reactions at high beam energies (>10 MeV/A). We, therefore, modified the SRM, specifically incorporating the energy dependence in the definition of critical angular momentum . The resulting modified SRM gave an improved theoretical estimate for the reactions we studied.
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(This article belongs to the Section Nuclear Theory and Experiments)
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Open AccessReview
On Invariant Vectors in the Presence of Electric and Magnetic Fields
Atoms 2023, 11(7), 105; https://doi.org/10.3390/atoms11070105 - 20 Jul 2023
Abstract
In this non-exhaustive review, we discuss the importance of invariant vectors in atomic physics, such as the Laplace–Runge–Lenz vector, the Redmond vector in the presence of an electric field, the Landau–Avron–Sivardièrevector when the system is subject to a magnetic field, and the supergeneralized
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In this non-exhaustive review, we discuss the importance of invariant vectors in atomic physics, such as the Laplace–Runge–Lenz vector, the Redmond vector in the presence of an electric field, the Landau–Avron–Sivardièrevector when the system is subject to a magnetic field, and the supergeneralized Runge–Lenz vector for the two-center problem. The application to the Stark and Zeeman effects are outlined. The existence of constants of motion in the charge-dyon system is also briefly mentioned.
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(This article belongs to the Special Issue Spectral Line Shapes in Plasmas, Including Cases with External Electric and Magnetic Fields and Laser Plasma Interaction)
Open AccessArticle
Role of Simple Spatial Gradient in Reinforcing the Accuracy of Temperature Determination of HED Plasma via Spectral Line-Area Ratios
by
, , , , and
Atoms 2023, 11(7), 104; https://doi.org/10.3390/atoms11070104 - 12 Jul 2023
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We report on the simulation of temperature gradients in tamped NaFMgO target-foil plasma, heated and backlit by z-pinch dynamic hohlraum radiation. Our approach compares the spectroscopic output of a collisional-radiative model (prismspect) with soft X-ray absorption spectra collected on Sandia National
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We report on the simulation of temperature gradients in tamped NaFMgO target-foil plasma, heated and backlit by z-pinch dynamic hohlraum radiation. Our approach compares the spectroscopic output of a collisional-radiative model (prismspect) with soft X-ray absorption spectra collected on Sandia National Laboratories’ (SNL) Z Pulsed Power Facility. The pattern of minimum is seen to agree with an efficient, three-parameter model. Results show that a negligible gradient in electron temperature is consistent with experimental data, justifying the assumptions of previous work. The predicted sensitivity of line spectra to the gradient-aligned profile of is documented for each spectral feature, so that the line-area ratio between a pair of spectral features may be assessed as a proxy for the existence and quantification of such gradients.
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Open AccessArticle
Role of Gas Pressure in Quasi-Phase Matching in High Harmonics Driven by Two-Color Laser Field
Atoms 2023, 11(7), 103; https://doi.org/10.3390/atoms11070103 - 07 Jul 2023
Abstract
The results of a study on the effect of pressure in a medium consisting of a set of gas jets separated by vacuum gaps, interacting with two-color laser fields formed by the fundamental and the second harmonics of a laser, are presented herein.
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The results of a study on the effect of pressure in a medium consisting of a set of gas jets separated by vacuum gaps, interacting with two-color laser fields formed by the fundamental and the second harmonics of a laser, are presented herein. It has been demonstrated that a decrease in pressure leads to a shift in the region of harmonics where quasi-phase matching (QPM) occurs towards shorter wavelength radiation, accompanied by an increase in the efficiency of amplification of these harmonics. A feature of this process is the identical power-law character of the shift in the region and the increase in the efficiency of harmonic QPM amplification. Additionally, the study presents the results of the effect of inaccurately setting the width of the gas jets on the shape of the spectrum of harmonic QPM amplification.
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(This article belongs to the Special Issue Recent Progress in Strong-Field Atomic and Molecular Physics)
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Variational Approaches to Two-Dimensionally Symmetry-Broken Dipolar Bose–Einstein Condensates
by
and
Atoms 2023, 11(7), 102; https://doi.org/10.3390/atoms11070102 - 06 Jul 2023
Abstract
It has been shown that quantum fluctuations in dipolar Bose–Einstein condensates (BECs) lead to a stabilisation against collapse, thereby providing access to a range of states with different symmetries. In this paper, we discuss variational approaches to approximately determine the phase diagrams for
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It has been shown that quantum fluctuations in dipolar Bose–Einstein condensates (BECs) lead to a stabilisation against collapse, thereby providing access to a range of states with different symmetries. In this paper, we discuss variational approaches to approximately determine the phase diagrams for dipolar BECs that are trapped along the dipolar orientation and otherwise infinite in the perpendicular direction (thermodynamic limit). The two-dimensional symmetry breaking occurs in the plane perpendicular to the polarisation axis. We show in detail how to derive approximate expressions that are valid in a region where modulations to an otherwise unmodulated perfect superfluid emerge gradually with a small modulation amplitude and compare the results to rigorous numerics.
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(This article belongs to the Special Issue Recent Trends on Quantum Fluctuations in Ultra-Cold Quantum Gases)
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Mean-Field Description of Cooperative Scattering by Atomic Clouds
Atoms 2023, 11(7), 101; https://doi.org/10.3390/atoms11070101 - 29 Jun 2023
Abstract
We present analytic expressions for the scattering of light by an extended atomic cloud. We obtain the solution for the mean-field excitation of different atomic spherical distributions driven by a uniform laser, including the initial build up, the steady state and the decay
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We present analytic expressions for the scattering of light by an extended atomic cloud. We obtain the solution for the mean-field excitation of different atomic spherical distributions driven by a uniform laser, including the initial build up, the steady state and the decay after the laser is switched off. We show that the mean-field model does not describe subradiant scattering due to the negative interference of the photons scattered by N discrete atoms.
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(This article belongs to the Section Cold Atoms, Quantum Gases and Bose-Einstein Condensation)
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Open AccessCommunication
Scattering of X-ray Ultrashort Laser Pulses on Bound Electrons in Dense Plasma
Atoms 2023, 11(6), 100; https://doi.org/10.3390/atoms11060100 - 16 Jun 2023
Abstract
We considered the resonance scattering of ultrashort laser pulses (USLP) on the bound electrons of hydrogen-like ions in a dense plasma. A process description was proposed in terms of full scattering probability during the time of pulse action. Dense plasma’s effect was demonstrated
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We considered the resonance scattering of ultrashort laser pulses (USLP) on the bound electrons of hydrogen-like ions in a dense plasma. A process description was proposed in terms of full scattering probability during the time of pulse action. Dense plasma’s effect was demonstrated at the resonance scattering cross-section spectrum, and the probability dependence on USLP carrier frequency and duration was obtained for the cases of isolated ions and ions in a dense plasma.
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(This article belongs to the Special Issue Atomic Physics in Dense Plasmas)
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Open AccessCommunication
Measurement of the Tensor-Analyzing Power Component T20 for Incoherent Negative Pion Photoproduction on a Deuteron
by
, , , , , , , , , , , , and
Atoms 2023, 11(6), 99; https://doi.org/10.3390/atoms11060099 - 15 Jun 2023
Abstract
New results for the -component of the tensor-analyzing power of the incoherent negative pion photoproduction are presented. The experiment was performed for the electron beam energy of 800 MeV at the VEPP-3 storage ring in 2021. To extract the
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New results for the -component of the tensor-analyzing power of the incoherent negative pion photoproduction are presented. The experiment was performed for the electron beam energy of 800 MeV at the VEPP-3 storage ring in 2021. To extract the -component, we used asymmetry with respect to the change in the sign of the tensor polarization of the deuteron target. Identification of the reaction events was carried out by the detection of two protons in coincidence. Experimental data were compared with the results of statistical simulation, considering the interaction between the and subsystems in the final state of the reaction.
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(This article belongs to the Section Nuclear Theory and Experiments)
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Open AccessReview
Neutron Interferometer Experiments Studying Fundamental Features of Quantum Mechanics
Atoms 2023, 11(6), 98; https://doi.org/10.3390/atoms11060098 - 15 Jun 2023
Abstract
Quantum theory provides us with the best account of microscopic components of matter as well as of radiation. It was introduced in the twentieth century and has experienced a wide range of success. Although the theory’s probabilistic predictions of final experimental outcomes is
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Quantum theory provides us with the best account of microscopic components of matter as well as of radiation. It was introduced in the twentieth century and has experienced a wide range of success. Although the theory’s probabilistic predictions of final experimental outcomes is found to be correct with high precision, there is no general consensus regarding what is actually going on with a quantum system “en route”, or rather the perceivable intermediate behavior of a quantum system, e.g., the particle’s behavior in the double-slit experiment. Neutron interferometry using single silicon perfect crystals is established as a versatile tool to test fundamental phenomena in quantum mechanics, where an incident neutron beam is coherently split in two or three beam paths with macroscopic separation of several centimeters. Here, we present quantum optical experiments with these matter-wave interferometers, studying the effect of the quantum Cheshire Cat in some variants, the neutron’s presence in the paths of the interferometer as well as the direct test of a commutation relation. To reduce disturbances induced by the measurement, the interaction strength is lessened and so-called weak interactions are exploited by employing pre- and post-selection procedures. All results of the experiments confirm the predictions of quantum theory; the observed behaviors of the neutron between the pre- and post-selection in space and time emphasize striking and counter-intuitive aspects of quantum theory.
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(This article belongs to the Special Issue Advances in and Prospects for Matter Wave Interferometry)
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Pulse Cycle Dependent Nondipole Effects in Above-Threshold Ionization
Atoms 2023, 11(6), 97; https://doi.org/10.3390/atoms11060097 - 12 Jun 2023
Abstract
In this study, we employ strong field approximation (SFA) to investigate the influence of the number of pulse cycles on above-threshold ionization within the framework of nondipole theory. The SFA enables the analysis of the ionization process under the dominance of the electric
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In this study, we employ strong field approximation (SFA) to investigate the influence of the number of pulse cycles on above-threshold ionization within the framework of nondipole theory. The SFA enables the analysis of the ionization process under the dominance of the electric field, compared to other factors such as the binding potential of an atom. Nondipole effects, including higher-order multipole fields, can significantly impact ionization dynamics. However, the interaction between nondipole effects and pulse cycles remains unclear. Therefore, we investigate the pulse cycle dependence of ionization and examine peak shifts in Kr and Ar atoms. Our findings have implications for comprehensively understanding the effects of electromagnetic fields on electron behavior. The insights gained from this study provide valuable guidance for future research in strong field ionization.
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(This article belongs to the Special Issue Recent Progress in Strong-Field Atomic and Molecular Physics)
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Structure and Bonding Patterns in C5H4 Isomers: Pyramidane, Planar Tetracoordinate Carbon, and Spiro Molecules
by
, , , , and
Atoms 2023, 11(6), 96; https://doi.org/10.3390/atoms11060096 - 10 Jun 2023
Abstract
We have theoretically investigated nine unusual isomers of the molecular formula C5H4 using coupled cluster (CC) and density functional theory (DFT) methods. These molecules possess non-classical structures consisting of two pyramidanes, three planar tetracoordinate carbon (ptC), and four
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We have theoretically investigated nine unusual isomers of the molecular formula C5H4 using coupled cluster (CC) and density functional theory (DFT) methods. These molecules possess non-classical structures consisting of two pyramidanes, three planar tetracoordinate carbon (ptC), and four spiro types of isomers. Both the pyramidanes (tetracyclo-[2.1.0.01,3.02,5]pentane; py-1 and tricyclo-[2.1.0.02,5]pentan-3-ylidene; py-2) are minima on the potential energy surface (PES) of C5H4. Among the three isomers containing ptC, (SP4)-spiro [2.2]pent-1-yne (ptC-2) is a minimum, whereas isomer, (SP4)-spiro [2.2]pent-1,4-diene (ptC-1) is a fourth-order saddle point, and (SP4)-sprio[2.2]pent-1,4-diylidene (ptC-3) is a transition state. The corresponding spiro isomers spiro[2.2]pent-1,4-diene (spiro-1), sprio[2.2]pent-1,4-diylidene (spiro-3) and spiro[2.2]pent-4-en-1-ylidene (spiro-4) are local minima, except spiro[2.2]pent-1-yne (spiro-2), which is a second-order saddle point. All relative energies are calculated with respect to the global minimum (pent-1,3-diyne; 1) at the CCSD(T)/cc-pVTZ level of theory. Quantum chemical calculations have been performed to analyze the bonding and topological configurations for all these nine isomers at the B3LYP/6-311+G(d,p) level of theory for a better understanding of their corresponding electronic structures. ptC-2 was found to be thermodynamically more stable than its corresponding spiro counterpart (spiro-2) and possesses a high dipole moment (μ = 4.64 D). The stability of the ptC structures with their higher spin states has been discussed.
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(This article belongs to the Special Issue Planar Tetracoordinate Carbon—Fifty Years and Beyond)
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Quasi-Static Lineshape Theory for Rydberg Excitations in High-Density Media
by
and
Atoms 2023, 11(6), 95; https://doi.org/10.3390/atoms11060095 - 10 Jun 2023
Abstract
This work presents a theoretical approach for lineshapes of Rydberg excitations in high-density media. In particular, we introduce the quasi-static lineshape theory, leading to a methodic and general approach, and its validity is studied. Next, using Sr as a prototypical scenario, we
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This work presents a theoretical approach for lineshapes of Rydberg excitations in high-density media. In particular, we introduce the quasi-static lineshape theory, leading to a methodic and general approach, and its validity is studied. Next, using Sr as a prototypical scenario, we discuss the role of the thermal atoms and core–perturber interactions, generally disregarded in Rydberg physics. Finally, we present a characterization of the role of Rydberg–core perturber interactions based on the density and principal quantum number that, beyond affecting the lineshape, could potentially apply to chemi-ionization reactions responsible for the decay of Rydberg atoms in high-density media.
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(This article belongs to the Section Cold Atoms, Quantum Gases and Bose-Einstein Condensation)
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Improved Line Intensity Analysis of Neutral Helium by Incorporating the Reabsorption Processes in a Helium Collisional-Radiative Model
Atoms 2023, 11(6), 94; https://doi.org/10.3390/atoms11060094 - 08 Jun 2023
Abstract
In this study, eight emission lines in the visible wavelength range of neutral helium were used to diagnose the electron density and temperature of the Large Helical Device (LHD) helium plasma instead of the conventional three-line method. The collisional-radiative (CR) model for low-pressure
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In this study, eight emission lines in the visible wavelength range of neutral helium were used to diagnose the electron density and temperature of the Large Helical Device (LHD) helium plasma instead of the conventional three-line method. The collisional-radiative (CR) model for low-pressure helium plasma was revised to include the optical escape factors for spontaneous transition from the n1P states to the ground state so that the influence of the absorption effect under optically thick conditions could be considered. The developed algorithm was based on fitting the number densities of eight excited states obtained using optical emission spectroscopy (OES). The electron density, electron temperature, ground-state density, and optical escape factors were selected as the fitting parameters. The objective function was set as the summation of the residual errors between the number densities measured in the experiment and those calculated using the revised model. A regularization term was introduced for the optical escape factor and optimized through bias and variance analyses. The results show that the agreement between the number density calculated by the algorithm and its counterpart measured in the experiment was generally improved compared to the method using three lines.
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(This article belongs to the Special Issue Plasma Spectroscopy and Plasma Diagnostics: From Classical to Sophisticated Methods)
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Open AccessEditorial
Editorial of the Special Issue “General Relativistic Atomic Structure Program—GRASP”
Atoms 2023, 11(6), 93; https://doi.org/10.3390/atoms11060093 - 06 Jun 2023
Abstract
The year 2022 marked the 10th anniversary not only of the journal but also of the international collaboration on Computational Atomic Structure [...]
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(This article belongs to the Special Issue The General Relativistic Atomic Structure Package—GRASP)
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Modification of Vibrational Parameters of a CO2 Molecule by a Laser Field: Impact on Tunnel Ionization
Atoms 2023, 11(6), 92; https://doi.org/10.3390/atoms11060092 - 05 Jun 2023
Abstract
In this paper, we theoretically study the laser-induced modification of the vibrational parameters of a carbon dioxide molecule regarding its tunnel ionization. Our study predicts a 5% increase in the ionization rate in anti-Stokes channels that corresponds to pumping the mode
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In this paper, we theoretically study the laser-induced modification of the vibrational parameters of a carbon dioxide molecule regarding its tunnel ionization. Our study predicts a 5% increase in the ionization rate in anti-Stokes channels that corresponds to pumping the mode up to . The molecule is imparted with an additional energy from the pre-pumped vibrational states, which is absorbed during ionization. As a result, the tunneling rate increases. This amplification of tunnel ionization of the CO gas target can potentially be used for the laser separation of carbon isotopes.
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(This article belongs to the Special Issue Recent Progress in Strong-Field Atomic and Molecular Physics)
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High-Order Above-Threshold Ionization Using a Bi-Elliptic Orthogonal Two-Color Laser Field with Optimal Field Parameters
Atoms 2023, 11(6), 91; https://doi.org/10.3390/atoms11060091 - 05 Jun 2023
Abstract
In the present paper, we study the high-order above-threshold ionization of noble-gas atoms using a bi-elliptic orthogonal two-color (BEOTC) field. We give an overview of the SFA theory and calculate the differential ionization rate for various values of the laser field parameters. We
[...] Read more.
In the present paper, we study the high-order above-threshold ionization of noble-gas atoms using a bi-elliptic orthogonal two-color (BEOTC) field. We give an overview of the SFA theory and calculate the differential ionization rate for various values of the laser field parameters. We show that the ionization rate strongly depends on the ellipticity and the relative phase between two field components. Using numerical optimization, we find the values of ellipticity and relative phase that maximize the ionization rate at energies close to the cutoff energy. To explain the obtained results, we present, to the best of our knowledge, for the first time the quantum-orbit analysis in the BEOTC field. We find and classify the saddle-point (SP) solutions and study their contributions to the total ionization rate. We analyze quantum orbits and corresponding velocities to explain the contribution of relevant SP solutions.
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(This article belongs to the Special Issue Recent Progress in Strong-Field Atomic and Molecular Physics)
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