The European Physical Journal D  Atomic, Molecular, Optical and Plasma Physics
Journal Prestige (SJR): 0.387 Citation Impact (citeScore): 1 Number of Followers: 29 Hybrid journal (It can contain Open Access articles) ISSN (Print) 14346060  ISSN (Online) 14346079 Published by SpringerVerlag [2469 journals] 
 Estimation of distancedistribution probabilities from pulsed electron
paramagnetic resonance (EPR) data of two dipolar interaction coupled
nitroxide spin labels using doubly rotating frames and leastsquares
fitting
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Abstract: A method, based on the doubly rotating frame (DRF) technique to calculate the basis DEER (Double Electron–Electron Resonance) signals [Physica B: Condensed Matter, 625, 413,511 (2022)] accurately by numerical techniques over a range of \(r\) values, where \(r\) is the distance between the two nitroxides in a biradical in a biological system, has been exploited to calculate the probabilities of distance distribution, \(P\left( r \right), \) by the use of Tikhonov regularization. It is demonstrated here by applying it to the data reported by Lovett et al. [J. Magn. Reson., 223, 98–106 (2012)] on a sample of bisnitroxide nanowire, P1, in deuterated orthoterphenyl solvent with 5% BnPy (d14oTP/BnPy) in semirigid state. An improvement in the agreement of the calculated signal with respect to the experimental signal and thus in the probabilities of the distance distribution, \(P\left( r \right)\) , so obtained, is found, as compared to that obtained using the kernel signals based on analytical expressions. Graphical abstract
PubDate: 20220519

 Potassium upconversion violet light generation under twocolor twophoton
excitation to 4D, 6S level
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Abstract: Twocolor nanosecond dye lasers were used to excite potassium vapor cell, and 404nm violet beam output was observed. This violet beam owns good collimation and transient properties, and its wavelength matches with the transition from potassium 52P3/2,1/2 doublet to the ground state. An analysis process shows that the violet light mechanism is attributed to twophotoninduced 42S1/2 → 42P3/2 → 42D3/2,5/2/62S1/2 transition, 42D3/2,5/2/62S1/2 → 52P3/2,1/2 SHRS (stimulated hyperRaman scattering), and FWM (fourwavemixing) processes; this is a thirdorder nonlinear optics process. Violet light doubletline intensity ratio was found to change while fine scanning of excitation wavelength; this shifting was thought related to the FWM resonant degree. Potassium violet light is expected to become new tunable light source. Graphical abstract
PubDate: 20220517

 Laboratory experiments on the radiation astrochemistry of water ice phases

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Abstract: Water (H2O) ice is a ubiquitous component of the universe, having been detected in a variety of interstellar and Solar System environments where radiation plays an important role in its physicochemical transformations. Although the radiation chemistry of H2O astrophysical ice analogues has been well studied, direct and systematic comparisons of different solid phases are scarce and are typically limited to just two phases. In this article, we describe the results of an indepth study of the 2 keV electron irradiation of amorphous solid water (ASW), restrained amorphous ice (RAI) and the cubic (Ic) and hexagonal (Ih) crystalline phases at 20 K so as to further uncover any potential dependence of the radiation physics and chemistry on the solid phase of the ice. Midinfrared spectroscopic analysis of the four investigated H2O ice phases revealed that electron irradiation of the RAI, Ic, and Ih phases resulted in their amorphization (with the latter undergoing the process more slowly) while ASW underwent compaction. The abundance of hydrogen peroxide (H2O2) produced as a result of the irradiation was also found to vary between phases, with yields being highest in irradiated ASW. This observation is the cumulative result of several factors including the increased porosity and quantity of lattice defects in ASW, as well as its less extensive hydrogenbonding network. Our results have astrophysical implications, particularly with regards to H2Orich icy interstellar and Solar System bodies exposed to both radiation fields and temperature gradients. Graphical abstract
PubDate: 20220517

 Spectral and dissociation characteristics of aluminum chloride in external
electric field
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Abstract: Aluminum chloride has great toxicity and threatens the ozone layer. The groundstate geometric structure and spectral characteristics are calculated for various external electric fields via DFT at the B3LYP/6–31 + G(d) basis set level. Aluminum chloride dissociation is directly given by calculating the molecular potential energy curve and potential energy surface. With the external electric field, the structure of aluminum chloride changes significantly. With increase in electric fields, the 1Al3Cl and 1Al4Cl bond lengths increase, and the total energy and energy gap initially increase and then decrease, whereas the dipole moment first decreases and then increases. Most vibrational frequencies of infrared and Raman spectra are redshifted. When the electric fields intensity is 0.040 a.u., the 1Al4Cl bond fracture, which means a dissociation of the molecule. When the electric field intensity is 0.045 a.u., the aluminum chloride appeared on another dissociation pathway, which may be concerted. These results are of great significance concerning the dissociation mechanism of aluminum chloride in external electric field. Graphical abstract
PubDate: 20220517

 Gauge dependence of spontaneous radiation spectrum in a timedependent
relativistic nonperturbative Coulomb field
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Abstract: Lamb triggered a continuous debate on the gauge choice for atomic interactions with electromagnetic fields, particularly with plane waves and the vacuum field. Modern technologies of Rydberg atoms and relativistic atomic beams make it possible to explore interactions with a more intriguing nonperturbative, adiabatic Coulomb field. In such cases, one would face the wellknown tricky issue about the physical significance of the scalar gauge potential when it is timedependent. We start attacking this issue by studying a simplest system: a onedimensional oscillator interacting adiabatically with a relativistic charge. We reveal that a gauge dependence much severer than the one Lamb observed is encountered when calculating the transient radiation spectrum of this oscillator by the externalfield method, which is currently the only available tool. The obtained peak frequency can differ by 10 MHz or larger for the commonly used Coulomb, Lorentz, and Multipolar gauges. Contrary to the popular view, we explain that such a gauge dependence is not really a disaster, but actually an advantage here: The relativistic boundstate problem is so complicated that a full quantumfield method is still lacking; thus, the externalfield approximation cannot be derived and hence not guaranteed. However, by fitting to experimental data, one may always define an effective external field, which may likely be parameterized with the gauge potential in a particular gauge. This effective external field would not only be of phenomenological use, but also shed light on the physical significance of the gauge potential. We thereby encourage further investigations of this fundamental problem with more realistic systems involving Rydberg atoms and relativistic atomic beams, both theoretically and experimentally. Graphic
PubDate: 20220516

 The scattering symmetries of tetrahedral quantum structures

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Abstract: The electrons associated with molecules and other small quantum structures exist in states that are bound or quasibound to the molecule. The quasibound states, which can significantly affect chemical reaction dynamics, have finite lifetimes and are associated with complex energy poles of the scattering matrix. Using Wigner–Eisenbud (Rmatrix) scattering theory, we examine the symmetry properties of the quasibound states of a moleculesize tetrahedral system, and we examine the relation of quasibound states to the scattering properties. In addition, using Rmatrix theory, we construct a nonHermitian Hamiltonian whose complex energy eigenvalues coincide with the bound and quasibound states of the molecule. We show that each bound state and quasibound state of the tetrahedral system belongs to a distinct irreducible representation of the tetrahedral group, and that an incident electron belonging to one irreducible representation can only scatter within the same irreducible representation. Graphic
PubDate: 20220516

 Optimization of highorder harmonic generation for the timeresolved ARPES

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Abstract: We experimentally investigated the optimized phase matching condition for high order harmonic generation as a source of timeresolved Angleresolved photoemission spectroscopy (TRARPES) applications. In the loose focusing scheme, we find that the divergence of harmonics decreases with the increase of gas cell length, while the maximum intensity is obtained with 10–15 mm gas cell. Our result shows that stable beam condition with best temporal resolution can be realized for TRARPES by using a longer gas cell (longer than 25 mm in our experiment), and an appropriate gas cell length can provide balanced condition for good beam intensity and good temporal resolution. Graphical abstract For the experiments carried out on HHGbased TR ARPES, the wavefront tilt of harmonic beam is inevitably introduced by the grating used in monochromator, leading to the boarding of pulse width and the dramatic decrease of the temporal resolution. A simple way to decrease the wavefront tilt is by optimizing the beam quality of high order harmonics. In our work, we aim to decrease the divergence of harmonic beam while keeping the enough intensity. We have experimentally investigated the intensity and beam divergence of high order harmonics generated in Ar for different gas cell condition. The divergence of harmonics decreases with the increase of gas cell length which is shown in (a), while the maximum intensity is obtained with 10 15 mm gas cell shown in (b). Our result c d shows that stable beam condition with best temporal resolution can be realized for TR ARPES by using a longer gas cell, and an appropriate gas cell length can provide balanced condition for good beam intensity and good temporal resolution.
PubDate: 20220516

 Goos–Hänchen shift observed from stratified medium

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Abstract: In this paper, we have theoretically examined Goos–Hänchen shift (GHS) obtained from a stratified epsilonnearzero (ENZ) medium placed in air. Transfer matrix method is used to calculate GHS for a sandwich structure composed of odd number of slabs. The impact of changing the material permittivity, thickness and number of slabs on GHS is discussed in detail for TE and TM polarized light. Significant increase in GHS is observed as the number of ENZ slabs in stratified structure is increased. When all the slabs have equal permittivity, published results for a single ENZ slab are recovered. The presented work will help in designing stratified ENZ medium with required GHS and reflectivity for optical sensors. Graphic abstract
PubDate: 20220512

 A prospective study on ionization of endohedral metallofullerene as

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Abstract: Since the discovery of endohedral metallofullerene, it has always been attractive among researchers in various fields of utilities. An encapsulated Au atom with fullerene can be an ideal active agent for enhancing the response of the ligand docking site of protein for cryoelectron microscopy. In this study, we have used high energy electron scattering to ionize encapsulated Au atom, which is docked in protein’s cavity. It is to identify the capabilities of encapsulated Au atom as a biomarker for cryoelectron microscopy. We have applied a fully relativistic calculation to calculate differential cross section and spin asymmetry with relativistic wave functions at the high impact energy. The obtained results reflect that endohedral metallofullerene can enhance the scattering amplitude of protein, which could be a biosensing tool for cryoEM, as well as the study of drug docking with any protein molecule. Graphic
PubDate: 20220511

 Dynamic behaviour of beta decay constant in Hlike atoms with intense
laser
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Abstract: Beta decay in hydrogenlike atoms is studied under the influence of a linearly polarized laser field. The oscillating electronic cloud under an intense laser field produces a timevarying field around the nucleus. The interaction of this electric field with the nucleus of the hydrogenic system is studied in terms of interaction between the electronic and nuclear charge densities. The nuclear transition matrix for beta decay is calculated by considering the interaction Hamiltonian, and the variations in the decay constant are analyzed. Graphic
PubDate: 20220506

 The role of dynamic absorption and polarization potentials in relativistic
excitation of xenon
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Abstract: Data on excitation of rare gases is mainly important in the study of lighting, plasma displays and lasers. From literature, cross sections data on electron impact excitation of lowlying resonance states of xenon atoms with both relativistic and nonrelativistic computations often differ with available experimental data mostly at low and intermediate impact energies and at intermediate scattering angles. With this in view, we have applied relativistic effects in a fully relativistic distortedwave born approximation approach to excitation of the lowest lying resonance states of a xenon target atom in a complex potential in order to solve the Dirac equations to obtain the free electron wavefunctions and corresponding excitation cross sections. Present differential cross sections (DCS) results from this study predict that absorption effects in the distortion potential generally have minimal effect on cross sections at impact energies below 50 eV, but then significantly improve these results in comparison with experiments as kinetic energy of the incident electron increases. Furthermore, it is evident that the energy dependent dynamic polarization potential adopted plays a major role in improving shapes of cross sections at low and near threshold impact energies, where other distortedwave methods fail to give satisfactory results. Graphical abstract We have applied a fully relativistic distortedwave (RDW) approach to inelastic excitation of the lowest J = 1 states of xenon in which a complex potential (SEPA = static (S), + exchange (SE), + polarization (SEP) and + absorption (SEPA)) is used to solve the Dirac equations to obtain electron initial and final wave functions \(\chi_{a}^{ + }\) and \(\chi_{b}^{ + }\) respectively). The transition matrix \(T_{a \to b}^{RDW} = \left\langle {\chi_{b}^{  } \left {V  U} \right A\chi_{a}^{ + } } \right\rangle\) is then used to obtain the differential cross sections. Theoretical studies on excitation of xenon J = 1 states [1–3] have not yet applied this approach. Experimental (Expt.) results are in bullets while calculations are in full and dotted lines. Present DCS results predict that the polarization potential plays a major role of improving cross sections at low and near excitation threshold while absorption does this above 50 eV.
PubDate: 20220506

 Photofragmentation dynamics study of ArBr $$_2$$ 2 $$(v=16,\ldots ,25)$$ (
v = 16 , … , 25 ) using two theoretical methods: trajectory surface
hopping and quasiclassical trajectories
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Abstract: The vibrational predissociation of van der Waals complexes has been the object of study using a wide range of theoretical and experimental methods, producing a large number of results. We focus here on the ArBr \(_2\) ( \(v=16,\ldots ,25\) ) system. For its study, we employ two important theoretical methods: the trajectory surface hopping (TSH) and the quasiclassical trajectory method (QCTM). In the first case, the dynamics of the system are reproduced on a potential energy surface (PES) corresponding to quantum molecular vibrational states. The possibility of hopping to other vibrational surfaces is also included, which can then lead to van der Waals bond dissociation. On the other hand, the second case consists of propagating the dynamics over a single potential energy surface. We incorporate the kinetic mechanism into the TSH method for better comparison of the evolution of the complex. Both methods allow us to study the dynamical behavior of the ArBr \(_2\) as well as several observables. We compute the lifetime, exit channel, rotational energy, and maximum angular momentum ( \(j_{max}\) ) of Br \(_2\) . We compare our results with previous experimental and theoretical work and also report new results for cases that have not previously been considered. Graphical abstract
PubDate: 20220506

 Design and development of dielectric barrier discharge setup to form
plasmaactivated water and optimization of process parameters
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Abstract: In the present work, a coaxial cylindrical plasma device has been designed and developed to generate dielectric barrier discharge to form plasmaactivated water (PAW). The voltage–discharge current characteristics and optical emission spectroscopy are performed to characterize the plasma and identify the formed plasma species. The impact of process parameters on physicochemical properties of PAW and on the concentration of reactive oxygen–nitrogen species is studied using a design of experiment methodology. The obtained results are analyzed using analysis of variance, effect estimation, marginal means, and regression analysis. The optimum values of process parameters to form PAW are determined using MATLAB fmincon function. The obtained results show that plasma–water exposure time and plasma discharge power significantly influence the physicochemical properties of PAW and the concentration of NO3‾ and NO2‾ ions in plasmaactivated water. Graphical abstract
PubDate: 20220505

 On the temperature of large biomolecules in ionstorage rings

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Abstract: A method to determine the temperature of molecular ions in an ionstorage ring is presented. Molecular ions were repeatedly irradiated by laser pulses over several hundred milliseconds, and the rate of fragmentation was used to determine the temperature of the photoexcited ions. The initial temperature of the ions before photoabsorption was in turn found from the microcanonical caloric curve for the molecule of interest. The temperature evolution of the protonated GFP chromophore in the ELISA storage ring was found for different starting conditions by this method. We find that the initial temperature of the ions when entering the ring depends on the iontrap temperature and the amount of buffer gas used in the trap. In particular, collisional heating during acceleration after the ion trap can be significant. Protonated GFP chromophores, produced under different conditions, were used to determine temperature effects on the gasphase absorption spectra. Graphical abstract
PubDate: 20220504

 Attosecond coupled electronnuclear dynamics of H $$_2$$ 2 molecule under
intense laser fields
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Abstract: Sequential double ionization and fragmentation dynamics of the H \(_2\) molecule exposed to an 750 nm, 4.5 fs elliptically polarized laser pulse is investigated by employing a quasiclassical model. In the model, momentumdependent auxiliary potentials are added to the Hamiltonian to account for nonclassical effects. Through theoretical exploitation of the molecular clock technique, the evolution of the vibrational wave packet of H \(_2^+\) formed by overthebarrier ionization of the H \(_2\) molecule is tracked between the first and second ionization events with the temporal resolution of 140 attoseconds. The role of electron correlation in strong field ionization is captured. Our results show that the quasiclassical model is quite capable of describing and predicting lightinduced multielectron processes in the molecules. Our study provides a simple path of explaining and understanding the physical mechanism of the strong field multielectron processes. Graphic abstract
PubDate: 20220503

 Publisher Correction to: Theoretical calculations of the photoionization
cross sections for the ground and lowest two excited states of Ni XVIII
ion
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PubDate: 20220502

 Structural physical approximation of partial transposition makes possible
to distinguish SLOCC inequivalent classes of threequbit system
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Abstract: Detection and classification of entanglement properties of a multiqubit system is a topic of great interest. This topic has been studied extensively, and thus we found different approaches for the detection and classification of multiqubit entangled states. We have applied partial transposition operation on one of the qubits of the threequbit system and then studied the entanglement properties of the threequbit system, which is under investigation. Since the partial transposition operation is not a quantum operation, we have approximated partial transposition operation in such a way that it represents a completely positive map. The approximated partial transposition operation is also known as structural physical approximation of partial transposition (SPAPT). We have studied in detail the application of SPAPT on a threequbit system and provided explicitly the matrix elements of the density matrix describing SPAPT of a threequbit system. Moreover, we propose a criterion to classify all possible stochastic local operations and classical communication inequivalent classes of a pure as well as mixed threequbit state through SPAPT map, which makes our criterion experimentally realizable. We have illustrated our criterion for detection and classification of threequbit entangled states by considering few examples. Graphical
PubDate: 20220426

 Nonrelativistic bound state solutions with αdeformed Kratzertype
potential using the supersymmetric WKB method: application to
theoreticinformation measures
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Abstract: In this work, we studied the bound states and quantum theoreticinformation measurements of an \(\alpha\) deformed Kratzertype potential with the Schrodinger equation. The ground state wave function in positionmomentum spaces and the energy spectra equations for arbitrary quantum numbers are obtained in closedform via the supersymmetric WKB method and Fourier transform. The obtained energy equation is bounded and reduces to the molecular Kratzertype energy and the hydrogenic Coulomb’s energy upon proper adjustment of potential parameters. The wave function was used to obtain the Fisher, Shannon, Rényi and Tsallis theoreticinformation measures numerically. Our results for the information measures obey the local Fisher inequality and the BialynickiBirula–Mycielski inequality. The Rényi and Tsallis entropies in positionmomentum spaces were obtained for the index number \(q = 0.5\) and \(q = 2\) as a function of the potential parameter. The results of the theoreticinformation quantities and probability densities revealed that the potential parameters strongly influence the localization and delocalization of the position of a nano particle. Graphical abstract
PubDate: 20220424

 Rabi oscillation and quantum decoherence of an optomechanical system with
a threelevel Vtype atom trapped in a twomode cavity
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Abstract: In this paper, the Rabi oscillation of a threelevel Vtype atom trapped in a twomode cavity field interacting with the phonon field is investigated by establishing a model in Hilbert space, and an analytical expression for the Rabi oscillation is given. We find that the Rabi oscillation is periodic or quasiperiodic by appropriately adjust the atomcavity coupling strength or phononcavity coupling strength, therefore, the periodicity of the Rabi oscillation does not depend on the resonance between the cavity and the micromechanical oscillator. The modulation period of Rabi oscillation and the number of oscillations in each period are given, which are obviously different from JC model. Compared with the period of JC model, the period of our model is larger under the same conditions, which makes it easier to study when it is used as the output signal. At the same time, the period of our model is more adjustable experimentally, furthermore, the period of Rabi oscillation will change greatly even when the parameter change is very small(except the resonance between the cavity and the micromechanical oscillator), which is helpful to study the sensitivity of the system and can also be used for the study of information amplification. And the quasi period is completely caused by the phonon field, so the quasiperiodicity is helpful for us to study the role of the phonons in the system. Furthermore, we study the quantum decoherence effect of the phonon field and cavity field and give the decoherence time scale and a constraint of the system, then extend it to the case of multiple modes cavity field. Graphical abstract
PubDate: 20220421

 Coherent manipulation of trapped Rb atoms by overlapping frequencychirped
laser pulses: theory and experiment
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Abstract: We present results of experimental and theoretical studies of coherent momentum transfer to rubidium atoms in a magnetooptical trap by pairs of counterpropagating frequencymodulated (chirped) laser pulses. The counterpropagating pulse pairs partially overlap each other leading to multiphoton interaction processes. We show experimentally that the mechanical momentum transferred to atoms in this scheme of interaction is larger than in the case of nonoverlapping pulse pairs acting separately on the atoms. Results of numerical simulations that take into account all relevant hyperfine energy states of Rb along with the influence of relaxation and repumping processes are in good agreement with obtained experimental results. Graphical abstract
PubDate: 20220420
