bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoionization of low-charged silicon ions
Authors: Buhr T , Stock S O , Perry-Sassmannshausen A , Reinwardt S , Martins M , Ricz S , Müller A , Fritzsche S , Schippers S
Published: June 2020

Synopsis

Single and multiple photoionization of Si1+, Si2+, and Si3+ ions have been investigated near the silicon K-edge using the PIPE setup at beamline P04 of the synchrotron light source PETRA III operated by DESY in Hamburg, Germany. Pronounced resonance structures are observed for all ions which are associated with excitation or ionization of a K-shell electron. The experimental cross sections are compared with results from theoretical calculations.
Coulomb explosion of polycyclic aromatic hydrocarbons induced by heavy cosmic rays: carbon chains production rates
Authors: Chabot M , Béroff K , Dartois E , Pino T
Published: June 2020

Synopsis

The interstellar medium contains both polycyclic aromatic hydrocarbons and cosmic rays. The frontal impact of a single heavy cosmic ray strips out many electrons. The highly charged species then relax by multi-fragmentation, potentially feeding the interstellar medium with hydrocarbon chains. We model both ionization(s) and fragmentation processes and compute the fragments production rates of particular interest for astrophysical models.
Double photoionization of He isoelectronic sequence
Authors: Koncevičiūtė J , Jonauskas V
Published: June 2020

Synopsis

Double photoionization of He-like ions is investigated using a few-step approach, that treats direct double photoionization as a sequence of two- (photoionization-ionization) and three-step (photoionization-excitation-ionization) processes.
Experimental alternative to investigate the radiation-induced radical chemistry at the molecular level
Authors: Beydoun A , Lecomte F , Nieuwjaer N , Desfrançois C , Manil B
Published: June 2020

Synopsis

This project aims to develop an original approach to investigate the damage at the molecular level on biomolecules from the indirect irradiation effects. We will construct a new device to put biomolecules in the gas phase, based on the soft laser desorption from microdroplets directly into vacuum, and this source will be coupled with an irradiation platform.
Nitrogen K-shell photoionization of NO+
Authors: Gharaibeh M F , Bizau J M , Cubaynes D , Guilbaud S , El Ghazaly M O A , Al Hagan O A
Published: June 2020

Synopsis

Photoionization measurements of NO+ at Nitrogen K-shell, performed at the SOLEIL Light Source will be presented. The main observed structure corresponds to the 1s to π* resonant transition.
Radiative and Auger cascades in Fe3+
Authors: Jonauskas V , Drabužinskis P , Kučas S , Koncevičiūtė J
Published: June 2020

Synopsis

Radiative and Auger cascades following creation of the 2s or 2p shell vacancy in the Fe2+ ion are studied by performing calculations for energy levels and subconfigurations. Radiative and Auger spectra and charge state distribution determined by cascade are investigated. Branching ratios of the cascade are analyzed and main decay mechanisms are identified for all levels of the studied configurations.
Cascade of elementary processes in Se1+
Authors: Jonauskas V , Kučas S , Masys Š , Koncevičiūtė J
Published: June 2020

Synopsis

Analysis of radiative and Auger cascade following creation of the K shell vacancy in the Se atom is presented. Calculations of radiative and Auger transition probabilities are performed by using Dirac-Fock-Slater approximation. Radiative and Auger spectra as well as ion yield produced by cascade are studied.
Absolute cross sections for electron capture and loss of O+ in water molecule
Authors: Oliveira V , Gomes A H A , Santos A C F , Tőkési K
Published: June 2020

Synopsis

Absolute cross sections for single and double electron loss and single and double electron capture for O+ projectiles colliding with water vapor have been measured. In addition, we have performed many-body clas-sical trajectory Monte Carlo calculations, where the O+ projectile was either one or more particle, depending on the model used. The water target is modeled as two virtual particles. The calculated cross sections are in agree-ment with the experimental data.
Photoemission delays in 2D model molecules
Authors: Wurmser B , Labeye M , Taïeb R , Caillat J
Published: June 2020

Synopsis

Photoelectron spectroscopy is one of the main techniques used to probe matter since the understand-ing of the photoelectric effect. Within the last decade, a new aspect has been given to spectroscopy, revisiting it in the time domain. It allows one to resolve the electron dynamics at the attosecond (10−18 s) time scale. Achieving such resolution experimentally brought one to establish innovative set up, and theoretical background is needed to validate, predict and interpret measurements. Much progress has been made in the attoscience field, this work is a step forward in understanding the electron dynamics for molecular continuum states at the attosecond timescale.
Single electron capture cross sections for collisions of multi-charged ions with helium-like atomic system
Authors: Samaddar S , Purkait K , Purkait M
Published: June 2020

Synopsis

A four-body distorted wave method (DW-4B) is applied to calculate the total cross section for single electron capture in the collisions of multi-charged ions with helium-like atomic system. The proper long range behavior of the Coulomb potential is introduced. The present theoretical method is satisfactory in the intermediate and high-energy regime and is quite reliable compared to other theoretical methods.
Ionization and electron capture in Li3+ + H2O collisions
Authors: Illescas C , Lombana M A , Méndez L , Rabadán I , Suárez J
Published: June 2020

Synopsis

Total cross sections for ionization and electron capture in Li3+ + H2O collisions are calculated at energies 20 ⩽ E ⩽ 750 keV/u. Three different models are applied: the classical trajectory Monte Carlo method, an expansion in terms of asymptotic-frozen-molecular-orbitals and the numerical solution of the time dependent Schrödinger equation. One-electron transition probabilities from the three methods show general good agreement and with those from the calculation of Luna et al Phys Rev. A
93, 052705.
Cross sections for electron capture process of biological molecules by proton and α-particle impact
Authors: Purkait K , Purkait M
Published: June 2020

Synopsis

Distorted wave model has been used to predict total cross sections (TCSs) of single electron capture process for several ion-biological molecule collisional systems in the intermediate and high energy regime. TCSs are calculated in the Independent Electron Model (IEM) In this work, we studied with water, nitrogen, oxygen, methane, adenine or cytosine targets impacted by protons and α-particles with kinetic energy ranging from 25 keV/amu to 10,000 keV/amu. It is observed that the present investigation produces results which are in good agreement with experimental observations for all cases.
Quasi-equilibrium in charge-state evolution for 1.0 and 2.0 MeV/u carbon ions after carbon foil penetration
Authors: Imai A M , Sataka M , Matsuda M , Okayasu S , Kawatsura K , Takahiro K , Komaki K , Shibata H , Nishio K
Published: June 2020

Synopsis

After our observation of “quasi-equilibrium” in charge-state evolution for 2.0 MeV/u sulfur ions after carbon foil penetration, we have extended the initial ions to 1.0 and 2.0 MeV/u carbon ions. A significant quasi-equilibrium was observed for 1.0 MeV/u C+C collisions, where the equilibrium mean charge-state was 4.9, while for 2.0 MeV/u C+C collisions, where the equilibrium mean charge-states was 5.6, was a weak quasi-equilibrium.
Single and double electron capture associated with characteristic K-shell X-ray emission for F9+,8+,7++Ar
Authors: La Mantia D S , Kumar P N S , Tanis J A
Published: June 2020

Synopsis

Cross sections for target Ar K-shell ionization associated with single and double electron capture, as well as the corresponding cross sections for total electron capture and the projectile F K x rays, were determined for 1.8-2.2 MeV/u F9+,8+,7+ projectiles. The Ar K x-ray coincidence cross section ratios for double to single capture are found to vary strongly with the incident charge state, with the ratios for F9+ well exceeding unity.
Production of molecular dications by electron impact investigated by (e, e+ion) measurement
Authors: Xu S , Wang Y , Ma C , Li Y , Zhou J , Ding L , Xu Z F , Dorn A , Ren X
Published: June 2020

Synopsis

We present (e, e+ion) measurements for double ionization of nitrogen and oxygen molecules employing the reaction microscope in which the momentum vectors for final-state charged reaction products are determined experimentally. By measuring the final state electrons in coincidence with the molecular dication, the related electronic states and, thus, the production mechanisms of these dications could be identified and studied in detail.
Non-local complex potential theory of dissociative electron attachment: inclusion of two vibrational modes
Authors: Ambalampitiya H B , Fabrikant I I
Published: June 2020

Synopsis

The nonlocal complex potential theory is developed to treat the dissociative electron attachment to molecules when more than one vibrational mode is allowed in the neutral molecule. Temperature-averaged cross sections for electron attachment to CF3Cl are obtained assuming two vibrational degrees of freedom.
Theoretical study of vibrational excitation and dissociative electron attachment of NO2 by an electron impact
Authors: Liu H , Santos S F , Yuen C , Cortona P , Kokoouline V , Ayouz M
Published: June 2020

Synopsis

Cross sections for vibrational excitation and dissociative electron attachment (DEA) of the nitrogen dioxide (NO2) molecule in collisions with low-energy electrons are determined theoretically. The thermally-averaged rate coefficients of vibrational excitation are presented for the temperatures from 10 K to 10000 K. The obtained DEA cross section for NO2 agrees well with experimental data.
Electron elastic collisions with Pu, Am and Lr actinide atoms
Authors: Msezane A Z , Felfli Z
Published: June 2020

Synopsis

The robust Regge-pole methodology which embeds the crucial electron correlations and the vital core-polarization interaction is used to explore negative-ion formation in the actinide atoms Pu, Am and Lr through the electron elastic total cross sections (TCSs) calculation. The TCSs are found to be characterized by ground, metastable and excited anionic formation, whence we extract the anionic binding energies and compare them with existing electron affinities. The TCSs exhibit both atomic and molecular behavior in addition to polarization-induced metastable TCSs.
Scattering of e∓ from H2O
Authors: Haque A K F , Shorifuddoza M , Patoary M A R , Uddin M A
Published: June 2020

Synopsis

Theoretical differential, elastic, total, momentum transfer, viscosity cross sections and spin-polarization for the elastic scattering of e∓ by H2 O molecule in the energy range 10 eV-10 keV have been calculated. These calculations have been carried out within the framework the Dirac partial wave analysis. We have employed a complex optical potential and additivity rule (AR) to compute the cross sections. Present results reasonably agree with available experimental data and other theoretical findings.
Separation of electronic states for small molecular ions by the mobility measurements in cooled He gas
Authors: Yamazaki T , Mori K , Tanuma H
Published: June 2020

Synopsis

In some cases of the ion mobility measurements in cooled He gas, we have observed the separation of electronic states for small molecular ions. Both NH+ and ND+ show the separation of X2Π and a4Σ states. The meta-stable

ND

2
+

and

NH

3
+

were observed, but these of

NH

2
+

and

ND

3
+

do not appear in the measurements. The reason of the isotope dependence in mobility measurement is discussed using the calculated potential energy curves for

NH

2
+

and

ND

2
+

.
New magnetized electron beam apparatus and measurement of total electron scattering cross section of N2O at intermediate energy region
Authors: Pyun H , Kim D C , Kim Y , Choi Y R , Park Y , Song M-Y , Kim Y-W , Yoon J-S , Cho H , Sullivan J P , Buckman S J
Published: June 2020

Synopsis

A new electron scattering apparatus is developed based on concepts from the positron system built by Surko et al. In an electron-version of the system, the electron beam is provided by a cathode and the rest of the system is correspondingly modified to a simpler system. The system was tested with argon to verify its operation. N2O is important in atmosphere and plasma, and in the intermediate energy region, there are two previous results which are in disagreement. We present here a result for the total electron cross section of N2O.
Energy loss of laser-accelerated ions in dense ionized matter
Authors: Zhao Y , Ren J , Deng Z , Qi W , Cheng R , Wang X , Liu W , Ma B , Yin S , Chen B , Feng J , Wang S , Fan Q , Cui B , Zhou X , Zhou W , Cao L
Published: June 2020

Synopsis

Knowledge about the energy loss of heavy ion in dense ionized matter is of great importance in fields such as inertial confinement fusion, fast ignition as well as intense heavy ion beam driven high energy density physics. The energy loss of 3.4 MeV proton in TAC foam plasma was measured on the XGIII laser facility. It was found that the measured energy loss is far above the Beth prediction.
Plasma dynamic simulations for reducing the erosion of discharge channel walls of Hall Effect Thruster (HET)
Authors: Priyanka B , Asif M M , Umesh R K
Published: June 2020

Synopsis

To assess and improve the design aspects during the design and development of HETs, it is essential to perform plasma dynamic simulations on these thruster designs. A 2D-3V (two dimensional-three velocity) Particle-in-cell Monte Carlo (PIC-MC) model has been used to simulate the standard SPT-100, and the design was optimized. Later, a completely new HET geometry has been simulated with an aim to optimize the thruster design with reduced plasma wall interaction.
Identification of EUV spectral profiles of laser-produced Cr plasmas
Authors: Wu L , Su M G , Min Q , Cao S Q , He S Q , Sun D X , Dong C Z
Published: June 2020

Synopsis

Laser-produced chromium (Cr) plasmas have been measured by using a temporal-spatially resolved laser-produced plasma emission spectroscopy technique. The emission peaks in the wavelength range of 6.5-15 nm were identified from the 3p-4d, 5d, and 3p-4s transition lines from Cr5+ to Cr10+ ions with aid of Cowan and Flexible Atomic Code (FAC) atomic structure calculations, and through comparative analysis between experimental and simulated spectra.
Evidence of trielectronic recombination for Ar ions in an EBIT
Authors: La Mantia D S , Biela W , Tanis J A , Warczak A
Published: June 2020

Synopsis

Trielectronic recombination has been investigated for Ar ions in a compact, room-temperature electron beam ion trap. A significant increase in hollow-core emission has been observed at the expected beam energy (~ 6.4 keV) for the KK→LMM resonance transition.
Absolute vibrational and electronic cross sections for low-energy electron scattering from condensed Thymidine
Authors: Lemelin V , Bass A D , Sanche L
Published: June 2020

Synopsis

Absolute vibrational and electronic excitation cross sections (CSs) for low-energy electrons (1-18 eV) scattering from condensed thymidine (dT) are measured with High-Resolution Electron Energy Loss Spectros-copy (HREELS). EEL spectra are recorded and the vibrational and electronic modes of dT identified. Absolute CSs for these modes are extracted from each spectrum by a fitting procedure. Resonances are observed in the incident energy dependence of the CSs, below 3 eV and near 4, 8 and 10 eV. The CSs are compared to those of its constituents: thymine and tetrahydrofuran.
Observation of two-electron one-photon X-ray transitions in collisions of slow Xe26+ ions with beryllium surface
Authors: Jabłoński Ł , Banaś D , Jagodziński P , Kubala-Kukuś A , Sobota D , Stabrawa I , Szary K , Pajek M
Published: June 2020

Synopsis

Two-Electron One-Photon (TEOP) X-ray transitions were observed for the first time in collisions of highly charged Xe ions with metallic Be surface. The intensities of TEOP X-rays are well described by performed MCDF for one-electron one-photon (OEOP) dipole-allowed transition of Paschen and Brackett series assuming constant TEOP/OEOP branching ratio. The importance of the Internal Dielectronic Excitation (IDE) in relaxation of hollow Xe ions/atoms has been evidenced and discussed.
Phonon contribution to grazing incidence fast atom diffraction
Authors: Gravielle M S , Miraglia J E
Published: June 2020

Synopsis

We address the effect of lattice vibrations of the crystal on grazing incidence fast atom diffraction (GIFAD) from insulator surfaces. To describe the phonon contribution to GIFAD we introduce a semi-quantum method, named Phonon-Surface Initial Value Representation (P-SIVR), which represents the surface with a harmonic crystal model, while the scattering process is given by the Surface Initial Value Representation approach including phonon excitations. P-SIVR results for Ne/LiF(001) are compared with other theoretical methods and available experiments.
Highly charged ion impact on graphene leading to the emission of low energy electrons
Authors: Schwestka J , Niggas A , Creutzburg S , Kozubek R , Madauß L , Heller R , Schleberger M , Facsko S , Wilhelm R A , Aumayr F
Published: June 2020

Synopsis

Recent experiments found that the neutralisation of highly charged ions interacting with a freestanding single layer of graphene proceeds on a femtosecond time scale. This ultra-fast deexcitation was attributed to Interatomic Coulombic Decay (ICD), a process in which core holes in the projectile are filled by previously captured outer electrons and the energy is transferred to electrons of the surrounding carbon atoms. ICD therefore predicts the emission of many low energy electrons. We now present experimental evidence that e.g. Xe40+ indeed emits up to 85 electrons with energies below 20 eV.
A quantitative study of ion guiding between two glass plates
Authors: DuBois R D , Giglio E , Tőkési K
Published: June 2020

Synopsis

The transmission of a 1 keV Ar+ beam between two glass plates was studied. We present experimental data with the goal to provide quantitative information about the buildup and decay of charge on the glass plates and how this correlates with the observed guiding.
Energy selective time of flight spectrometer to study low energy dissociation channels of PAHs
Authors: Vinitha M V , Kadhane U
Published: June 2020

Synopsis

Dissociation channels induced by sequential UV multiphoton absorption of vapour phase fluorene cation is investigated using energy selective ToF mass spectrometer. Neutral fluorene molecule is ionized by resonantly enhanced multiphoton absorption and dissociated in the same photon field. The main goal of this experiment is to determine the rate constants of statistical dissociation channels of PAH cations for a wide range of internal energies.
Radiodosimetry endpoints obtained with the TILDA-V Monte Carlo tracking structure code
Authors: Quinto M A , Alcocer-Avila M E , Monti J M , Weck P F , Fojón O A , Rivarola R D , Champion C
Published: June 2020

Synopsis

The present study aims at scrutinizing at the nanometer scale the radiodosimetry endpoints induced by ion beams in a realistic biological medium. In this context, self-consistent quantum mechanical modeling of the ionization and the electron capture processes are reported within the continuum distorted wave-eikonal initial state (CDW-EIS) framework for both isolated water molecules and DNA components impacted by ions.
State-dependent fragmentation of protonated uracil and uridine
Authors: Pitzer M , Ozga Ch , Küstner-Wetekam C , Reiß Ph , Knie A , Ehresmann A , Jahnke T , Giuliani A , Nahon L
Published: June 2020

Synopsis

Protonated uracil (m/z 113) and uridine (m/z 245) were exposed to synchrotron radiation in the photon energy range of 4.5 to 9 eV. The yield of various fragments as a function of photon energy shows maxima that can be attributed to excited electronic states and compared to calculated vertical excitation energies. For the nucleoside uridine, much less fragments were observed, indicating a stabilization of the nucleobase through the attached sugar molecule.
Convergent close-coupling calculations of positron collisions with the hydrogen negative ion
Authors: Fursa D V , Utamuratov R , Kadyrov A S , Bray I
Published: June 2020

Synopsis

Convergent close-coupling method has been applied to positron scattering by the hydrogen negative ion. Internal consistency of the method and convergence of the cross sections are achieved with use of both the single- and two-centre approaches. Calculations were performed using accurate target wave functions obtained with the multi-core approach.
Towards investigations of pre-cooled ions stored in the RICE storage ring via action spectroscopy
Authors: Chartkunchand KC , Menk S , Hirota A , Igosawa R , Kuma S , Nakano Y , Azuma T
Published: June 2020

Synopsis

A new cryogenic linear ion trap beamline has been commissioned for use with the RIKEN Cryogenic Electrostatic (RICE) storage ring. Testing of the beamline at room-temperature and cryogenic conditions was conducted using methylene blue cations MB+ and carbon cluster anions Cn
−. Action spectroscopy measurements of pre-cooled Cn
− anions injected into RICE will help determine the effectiveness of the so-called Pre-Trap Beamline, as well as provide structural and dynamical information on these cluster anions at cryogenic temperatures.
Final state resolved mutual neutralization of Li+ and D−
Authors: Eklund G , Grumer J , Rosén S , Najeeb P K , Zettergren H , Cederquist H , Barklem P S , Schmidt H T
Published: June 2020

Synopsis

We have performed a merged beam experiment on mutual neutralization of Li+ and D−, at center of mass energies close to 0 eV using the DESIREE storage rings. The final state channels Li(3s) and Li(3p+3d) are resolved and the branching ratio is found to be more equal than predicted from theoretical models.
Development of a detector to register low-energy, charge-changed ions from ionization experiments at CRYRING@ESR
Authors: Borovik A , Weber G , Hilbert V , Lin H , Pfäfflein P , Zhu B , Hahn C , Lestinsky M , Schippers S , Stöhlker Th , Rothhardt J
Published: June 2020

Synopsis

A detector setup for registering ion species between the poles of a dipole magnet at CRYRING@ESR has been developed. It is based on a scintillator delivering light via a quartz light guide onto a semiconductor photomultiplier. The detector is capable of operating in a strong magnetic field. It can be swiftly retracted from the exposition area during the beam injection into the ring and repositioned back for the measurement cycle to avoid unnecessary exposition and, thus, to increase the scintillator life time.
Precision Measurements of the Fundamental Properties of the Proton and Antiproton
Authors: Smorra C. , Mooser A.
Published: June 2020

Precision measurements comparing the fundamental properties of conjugate particles and antiparticles constitute stringent tests of CPT invariance. We review recent precision measurements of the BASE collaboration, which improved the uncertainty of the proton and antiproton magnetic moments and the comparison of the proton-to-antiproton charge-to-mass ratio. These measurements constitute the most stringent tests of CPT invariance with antiprotons. Further, we discuss the improved limit on the antiproton lifetime based on the storage of a cloud of antiprotons in the unique BASE reservoir trap. Based on these recent advances, we discuss ongoing technical developments which comprise a coupling trap for the sympathetic cooling of single (anti-)protons with laser-cooled beryllium ions, a transportable trap to relocate antiproton measurements into a high-precision laboratory, and a new experiment to measure the magnetic moment of helium-3 ions, which will improve absolute precision magnetometry.
Machine learning for analysing ab initio molecular dynamics simulations
Authors: Häse Florian , Galván Ignacio Fdez. , Aspuru-Guzik Alán , Lindh Roland , Vacher Morgane
Published: June 2020

Post-calculation analyses are often required to extract physical insights from ab initio molecular dynamics simulations. In the present work, we use different machine learning classifiers to take a new perspective on the decomposition reaction of dioxetane. Upon thermally activated decomposition, dioxetane can form products in an electronically excited state and can thus chemiluminesce. Simulated dynamics trajectories exhibit both successful and frustrated dissociations. As an exhaustive and systematic study of the decomposition mechanism “by hand” is beyond feasibility, machine learning models have been employed to study the relevant nuclear distortions governing molecular dissociation. According to all classifiers used in the study, the two sets of geometries differ by the in-phase planarisation of the two formaldehyde moieties. New insights are obtained from this analysis: if both moieties are not planar enough when the dissociation is attempted, it is frustrated and the molecule remains trapped. The postponing of the decomposition reaction by the so-called entropic trap enhances the chemiexcitation efficiency.
Positron collisions with targets of biological and technological relevance
Authors: Barbosa Alessandra Souza , Sanchez Sergio D’A , Bettega Márcio H F
Published: June 2020

In this work we present calculated cross sections for elastic scattering of low-energy positrons by molecules, obtained with the Schwinger multichannel method. We extended a previous study on the role of polarization effects in the positron-allene scattering and also present some preliminary results for positron collisions with cyclopentane. We also compare the differential cross sections of benzene and its azaderivative pyrimidine at selected energies, where similar angular behaviour was found.
Selective bond scission in formic acid by low-energy electrons
Authors: Griffin Brandon , Moradmand Ali , Williams Joshua , Belkacem Ali , Rescigno Thomas N , Trevisan Cynthia , McCurdy C William , Weber Thorsten , Slaughter Daniel S
Published: June 2020

We report recent results of mass-resolved anion fragment momentum imaging experiments to investigate dissociative electron attachment to formic acid, for incident energies between 5 eV and 9 eV. A remarkable site-selectivity is found for a resonance at 8.5 eV by comparing anion fragment yields for two deuterated isotopologues of formic acid. This results in an H− fragment from the O-H bond of the transient anion, with negligible contribution from C-H break. In contrast, a lower-energy resonance at 7.1 eV dissociates by C–H or O–H break to produce H− and the neutral radicals HOCO or HCOO.
Electron attachment and quantum coherence in molecular hydrogen
Authors: Prabhudesai Vaibhav S , Mason Nigel J , Krishnakumar E
Published: June 2020

Single electron attachment to a molecule may invoke quantum coherence in different angular momentum transfer channels. This has been observed in the 14 eV dissociative electron attachment resonance in molecular hydrogen where a coherent superposition of two negative ion resonant states of opposite parity is created, with the s and p partial waves of the electron contributing to the attachment process. Interference between the two partial wave contributions leads to a forward – backward asymmetry in the angular distribution of the product negative ions. Since these two resonant states dissociate to the same n = 2 state of H and H−, this asymmetry is further modified due to interference between the two paths of the dissociating molecular negative ion along different potential energy curves. This interference manifests as a function of the electron energy as well as isotopic composition. This case is akin to the quantum interference observed in photodissociation by one-photon vs two-photon absorption.
Positronium collisions with atoms and molecules
Authors: Wilde R S , Fabrikant I I
Published: June 2020

We describe recent theoretical efforts to explain the observed similarity between electron and positronium (Ps) scattering with both atoms and molecules. In order to perform these calculations at a more ab initio level we have developed a Free Electron Gas (FEG) approximation to the exchange and correlation potentials similar to that used in electron-molecule scattering. The FEG results give good agreement with experiment above the Ps ionization threshold and exhibit resonance features below the threshold. To take account of the effect of orthogonality between the scattered electron and the target wavefunctions we have used an orthogonalizing pseudopotential (OPP). The FEG plus OPP results give good agreement with experiment for Ps-rare-gas scattering. Preliminary results for Ps-H2 scattering also agree well with experiment and demonstrate the importance of including orthogonality for scattering below the Ps ionization threshold.
Projectile Coherence Effects in Simple Atomic Systems
Authors: Schulz M , Hasan A , Lamichhane B , Arthanayaka T , Dhital M , Bastola S , Nagy L , Borbély S , Járai-Szabó F
Published: June 2020

Recent studies of projectile coherence effects in ion-atom collisions are presented. For intermediate-energy proton collisions an extensive literature provides strong support for the importance of such effects. In this regime coherence effects are now used as a tool to study the few-body dynamics very sensitively. In contrast, for high-energy ion impact the literature is much sparser and here an important role of coherence effects cannot be regarded as being established. In this context, a recent claim that in COLTRIMS experiments the coherence properties are determined only by the target beam is rebutted.
An introduction to Bayesian statistics for atomic physicists
Authors: Trassinelli M.
Published: June 2020

We present an introduction to some concepts of Bayesian data analysis in the context of atomic physics. Starting from basic rules of probability, we present the Bayes’ theorem and its applications. In particular we discuss about the limits of classic statistics methods and in which cases a Bayesian analysis is mandatory. Moreover, we show how probability values can be assigned to different possible models (different numbers of peaks, type peak profile, etc.) from the analysis of experimental data.
Disentangling spectral phases of interfering autoionizing states from attosecond interferometric measurements
Authors: Petersson C L M , Barreau L , Klinker M , Camper A , Marante C , Gorman T , Kiesewetter D , Argenti L , Agostini P , González-Vazques J , DiMauro L F , Salières P , Martín F
Published: June 2020

Synopsis

The spectral phase of the autoionising neon continuum has been probed via interferometric pump-probe measurements as well as ab initio, full-electron, time-dependent, theoretical calculations in energy intervals containing several auto-ionising. Theory and experiment are in excellent agreement. Despite the complex energy-dependence of the phase, a very simple model has been used to disentangle the contribution by different resonances. This work extends the applicability of reconstruction methods to multi-resonance regions of autoionising continua - a common scenario in multi-electron systems.
Phase reconstruction of high-order harmonics by quantum path interference
Authors: Olofsson A , Ibrakovic N , Ek S , Bengtsson S , Simpson E R , Mauritsson J
Published: June 2020

Synopsis

We present a method to retrieve the phase of XUV light generated through high-order harmonic generation, by observing the intensity dependence of the interference pattern in the far-field. This interference pattern arises from electron trajectories in the generation process. These trajectories spend different time in the continuum and the phase of the generated light will therefore depend differently on the instantaneous intensity of the driving field. By changing the intensity of the driving field the phase of the contributing trajectories can be extracted.
Sideband selection in XUV + IR photoionization
Authors: Picca R Della , Gramajo A A , López S D , Arbó D G
Published: June 2020

Synopsis

We consider the ionization of argon atoms induced by a femtosecond laser pulse composed by overlapping extreme ultraviolet and infrared fields. We study several geometrical arrangements within the polarization vectors and emission direction that determinate only odd or even sideband peaks are present in the photoelectron spectrum.
Atomic and molecular suite of R-matrix codes for ultrafast dynamics in strong laser fields and electron/positron scattering
Authors: Wragg J , Benda J , Mašín Z , Armstrong G S J , Clarke D D A , Brown A C , Ballance C , Harvey A G , Houfek K , Sunderland A , Plummer M , Gorfinkiel J D , van der Hart H
Published: June 2020

Synopsis

We describe and illustrate a number of recent developments of the atomic and molecular ab initio R-matrix suites for both time-dependent calculations of ultrafast laser-induced dynamics and time-independent calculations of photoionization and electron scattering.
Temporal metrology for advanced ultrashort XUV sources
Authors: Sinyakova T , Bomme C , Bourassin-Bouchet C , Chopineau L , Cubaynes D , Dakroub L , Garcia G , Pandey A , Papagiannouli E , Guilbaud O , Quéré F , Klisnick A
Published: June 2020

Synopsis

A new VMI spectrometer has been developed in order to enable the single-shot characterization of different ultrashort XUV sources through laser-dressed photoionization. The instrument has been commissioned with a plasma-based XUV laser and, then, implemented on a high harmonics source based on a plasma mirror.
Time-resolved interferometric photoemission from Cu(111) and Ni(111) surfaces
Authors: Ambrosio M J , Thumm U
Published: June 2020

Synopsis

We calculated spectra and phases for photoemission from Cu(111) and Ni(111) surfaces. Our numerical model reproduces recently measured final-state shape resonances of the photoelectron in the substrate potential.
Generation and characterization of isolated attosecond pulses for coincidence spectroscopy at 100 kHz repetition rate
Authors: Witting T , Furch F , Osolodkov M , Schell F , Menoni C , Schulz CP , Vrakking M J J
Published: June 2020

Synopsis

An attosecond pump-probe beamline with 100 kHz repetition rate for coincidence experiments has been developed. It is based on non-collinear optical parametric chirped pulse amplification and delivers 100 μJ sub-4 fs to an high-harmonic generation source. Details on the generation and characterization of isolated attosecond pulses will be presented.
Attosecond angular streaking on H2 with all-ionic fragments detection
Authors: Quan W , Zhao M , Serov VV , Wei M Z , Zhou Y , Lai X Y , Kheifets A S , Liu X J
Published: June 2020

Synopsis

We explore a novel attosecond angular streaking scheme on H2 based on the all-ionic dissociative fragments detection. We aim to reveal the same information from the ionic attoclock as extracted from conventional attoclock measurements [1]. We examine the validity of the axial recoil approximation questioned in [2]. The advantage of the proposed scheme is that it does not rely on the adiabatic electron tunneling hypothesis which has raised the ongoing controversy of a finite tunneling time in the attosecond community [3]
Gauge-invariant time-dependent configuration interaction singles method: applications to high-harmonic generation from atoms
Authors: Teramura T , Sato T , Ishikawa K L
Published: June 2020

Synopsis

We present gauge-invariant reformulation of time-dependent configuration interaction singles (TDCIS) method and its applications to high-harmonic generation (HHG) from three-dimensional atoms. The conventional TDCIS method suffers from a violation of gauge-invariance, which prevents efficient simulations of high-field phenomena within the velocity gauge. In our reformulation, rotated velocity gauge transformed from the length gauge is employed instead of the velocity gauge. We simulate HHG from atoms and show gauge-invariance and performance of our rotated velocity gauge.
Two-photon laser-assisted electron scattering on Hydrogen atom
Authors: Kornev A S , Zon B A
Published: June 2020

Synopsis

We considered the influence of light-dressed-atom effect on two-photon laser-assisted electron-atom scattering in the Born approximation. We performed calculations for the ground state of a Hydrogen atom. For small scattering angles, the main contribution to the cross section is made by the combined process, when one of the photons is absorbed by the atomic electron and the second one by the scattered electron. However, in the UV region, when two-photon resonances with highly excited atomic states arise, the main contribution is determined by the inverse polarization Bremsstrahlung absorption.
Dynamic photoemission interference of hydrogen atoms in intense ultra-fast elliptically polarized extreme ultraviolett pulses
Authors: Li G , Wang N , Wang J , Liu A , Thumm U
Published: June 2020

Synopsis

We investigated dynamic interference (DI) in the photoionization of ground-state hydrogen atoms by intense extreme-ultraviolet (XUV) pulses with elliptical polarization. Numerically solving the time-dependent Schrodinger equation, we demonstrate that DI occurs not only in linearly but also in elliptically polarized pulses.
Influence of alkaline earths on EPR spectra of lithium borate glasses doped with Fe (III) ions
Authors: Bhogi Ashok , Kistaiah P.
Published: June 2020

Lithium borate glasses containing Fe (III) transition metal ion having composition 15RO-25Li2O-59B2O3-1Fe2O3 (where R= CaO, SrO and BaO) are synthesized via melt quench route. These glasses were characterized using X-ray diffraction (XRD). Electron paramagnetic resonance spectra of prepared glasses have been studied. The recorded spectra mainly consists of an intense resonance signals at g ∼ 4.282 and also at g ∼ 2.0032 along with a shoulder in the region of g ∼ 8.033 which is a characteristic of iron ions in the (3+) valence state in all the studied glasses. The number of spins participating in resonance (N) and its paramagnetic susceptibilities (χ) have also been evaluated. The spin concentration and the paramagnetic susceptibility at g = 2.0032 and at g = 4.282 increase by the substitution of alkaline earths from CaO to BaO respectively. The peak-to-peak line width ΔB for the resonance lines at g ≈ 4.282 and at g ≈ 2.0032 and the line intensity of the resonance centered at g ≈ 4.282 and at g ≈ 2.0032 have been evaluated. This EPR spectra has been analyzed in the light of different oxidation states of iron ions in order to understand the influence of alkaline earths as modifier oxide on the structure of glass matrix.
Design and Development of a Low-Cost Magnetic Induction Spectroscopy (MIS) Instrumentation
Authors: Bera Tushar Kanti , Maiti Toushik
Published: June 2020

Design and development procedure of a low-cost Magnetic Induction Spectroscopy (MIS) instrumentation has been presented. Along with the mathematical model of the electromagnetic system, MIS instrumentation is developed with two windings of suitable turns using enamelled copper wires of required cross-sectional area. The variable voltage multifrequency function generator developed to generate the magnetic field lines is used to excite the primary coil. The voltage developed at the secondary winding due to the Faraday’s electromagnetic induction principle is acquired to sense the permeability of the different materials placed as the core of the electromagnetic interface. The SNR has been studied for different amounts of voltages and frequencies of the electrical excitation applied at primary winding. The advantages and limitations of the system have been described along with the future work and possible applications of the system.
Synthesis, structure and optical properties of Indium filled CoSb3 nanomaterials
Authors: Uday Kumar M , Swetha R , Kumari Latha
Published: June 2020

The nano-sized InyCoSb3 skutterudites (y = 0.0125, 0.025, 0.0375 and 0.0625) were synthesized by solvo-/hydrothermal method at 240 °C for 24 hours. The surface morphology of as-synthesized samples analyzed by Field Emission Scanning Electron Microscope (FESEM) shows nanoparticles with size of around 50 nm depicting narrow size distribution and Electron X-ray diffraction spectroscopy (EDX) spectrum confirms the purity of the In-filled CoSb3 nanomaterials. The powder X-ray diffraction (pXRD) pattern reveals all the compositions showing diffraction peaks indexed to cubic phase of CoSb3 with Space group

Im

3
¯

. However, no significant variation in the pXRD pattern of In filled CoSb3 as compared to pure CoSb3 justifies the successful filling of voids in cage-like structure of CoSb3 with Indium. FTIR spectra of In filled CoSb3 presents vibration modes below 1000 cm−1 corresponding to Co-Sb bonding and Cobalt complex. A significance of In filling into CoSb3 structure is also evident. A wide absorption has been witnessed from UV region to large part of visible region, hence indicating the effect of nanoparticle, agglomeration and filling.
Growth, Optical and Thermal properties of Co2+ doped copper tartrate single crystals at different environmental conditions.
Authors: Pradeepkumar K V , Jagannatha N , Rohith P S
Published: June 2020

Cobalt doped Copper Tartrate (CoCT) crystals were grown in silica gel medium using single diffusion methods at room temperature, passing semiconductor laser and passing various UV visible radiation. The optimum conditions were obtained by varying parameters such as gel concentration, pH of gel, gel setting time, the concentration of reactance. The presence of cobalt, copper, carbon, and oxygen is confirmed by the Energy dispersive X-ray spectroscopy (EDX). The crystals obtained, are regular or elongated shaped depending on the growth and environmental conditions. The grown crystals are characterized by FTIR and PXRD. TGA studies explain the thermal behavior of the grown CoCT crystal. UV-Vis-NIR transmission spectroscopic analysis measured the energy gap and, to study the optical transparency of the grown crystals.
First-principles study of structural, elastic, electronic and optical properties of cubic perovskite LiMgF3 for novel applications
Authors: Ephraim Babu K. , Neeraja K. , Deenabandhu D. , Vijaya Ratna A. Mary , Venkata Kumar V. , Bueala Kumari K. , Taddesse Paulos , Tewodros Aregai G. , Mehar MVK , Vikram Babu B. , Samatha K. , Veeraiah V.
Published: June 2020

Structural, elastic and optoelectronic properties of materials are important to identify their applications in technology. In the present paper LiMgF3 is investigated to obtain these properties using the highly accurate full-potential linearized augmented plane wave (FP-LAPW) method. The exchange correlation effects are included through the generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) exchange potential. The structural optimization of LiMgF3 is compared with previous results and is found to be in good agreement with those results. The predicted band structure shows an indirect (M-Γ) bandgap of 6.1 eV. The elastic properties such as elastic constants, anisotropy factor, shear modulus, Young’s modulus, Poisson’s ratio are calculated and based on these calculations it is found that this compound is elastically stable and brittle in nature. The contribution of different bands to the band structure is analyzed from the total and partial density of states curves. Optical properties like real and imaginary parts of dielectric function, refractive index, extinction coefficient, reflectivity, energy loss function, conductivity and absorption coefficient are presented. Based on the optical properties of the compound, it is predicted that LiMgF3 is suitable for optoelectronic devices.
Battery Energy Storage Technologies for Sustainable Electric Vehicles and Grid Applications
Authors: Lakshmi G Sree , Olena Rubanenko , Divya G , Oleksandr Rubanenko
Published: June 2020

The energy consumption in worldwide has been increasing rapidly, due to increase in world population. This energy consumption growth is apparently impacting on the environment and the society. This has accelerated the development and deployment of Renewable Energy Sources (RES) harvesting technologies and facilities. The global electricity production by RES by the end of 2016 is accounted to 24.4%. This increase in RES has highlighted the next big challenge, storage of energy when demand is lower than the supply. There are many energy storage technologies existing from decades. Battery technologies have the highest cost reduction potential at the moment. Battery technologies are delivering significant advances in a wide range of industries, from electrical vehicles to renewable power. From the discovery of electrical energy, there is a great need to store the electrical energy generated for use on demand. Energy Storage Systems (ESS) is used to store the excess electricity when a power production is greater than consumption. ESS play very important role for off-grid storage applications to back up Renewable Energy such as Solar and Wind power, used by people who live or work in remote areas. Electrical energy can be stored in different forms including Electrochemical-Batteries, Kinetic Energy-Flywheel, Potential Energy-Pumped Hydro, and Compressed Air (CAES). This paper gives the current state of battery storage technologies, its main challenges, its applications and actions for future.
Additive Manufacturing for VADs and TAHs - a Review
Authors: Puppala A K , Sonnati V , Gangapuram S
Published: June 2020

Heart disease or Advanced/Congestive Heart Failure (CHF) is one of the serious causes of death. Due to availability of low volumes of donor hearts, there has been an ongoing development of Mechanical Circulatory Support (MCS): Ventricular Assist Devices (VADs) and total heart replacement by Total Artificial Hearts (TAHs) for over 60 years. MCS systems had seen three phases of advancement. The first generation were largely mechanical devices and had pulsatility in their action, but were highly cumbersome, unreliable due to fatigue cracks and required an external pneumatic power and control. Smaller and continuous flow devices are the second generation MCS devices. Because of compact sizing they were suitable for implantations and were more durable than the first generation devices. Problems like pump thrombosis drove the development of motors with levitating or hydrodynamic rotors, leading to the development of third generation devices. Manufacturing of these electromagnetic devices for implantation has to adhere to the constraints of compatibility, space and weight. With the advent of new biomaterials, additive manufacturing is reportedly playing a significant role. Additive manufacturing reported for electromagnetic and electronic components had yielded considerably good performance. This paper reviews materials in electrical and electronics and also in bio medical sector suitable for Additive Manufacturing. An attempt is made to identify the materials that may be suitable for VADs and TAHs and the challenges to use AM techniques that complement each other to create next generation integrated-VADs and integrated-TAHs.
Synthesis and Characterization of Carbazole Based Donor-Acceptor-Donor Type Polymer for NLO Applications
Authors: Balakrishna K. , Sampath R. , Vishwam T. , Samui A. B. M. , Joshi P. , Mohan S.Raj
Published: June 2020

Carbazole based NLO polymer was synthesized by using Knoevenagel condensation. The polymer is found to be fully soluble in high polar solvents like dimethyl formamide and dimethylsulphoxide. By using GPC and tetrahydrofuran as a solvent, the molecular weight is found to be 5000 g/mol. Thermal analysis exhibited thermal stability of the polymer up to 400 °C and glass transition temperature (Tg) at 214 °C. The polymer film has good optical transparency. The non-centrosymmetry in the film was induced by corona poling for second order NLO property, whereas z-scan technique is used to understand third order NLO property. The effective TPA coefficient (β) found to be 5.1 X 10−12 m/W. Computational study indicated that the total charge is located at the center of the molecule in HUMO case whereas in the case of LUMO the charge is spreads out from the center of the molecule.