bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of electric discharge collocated with gas jet in supersonic airflow
Authors: Efimov A V , Firsov A A , Kolosov N S , Leonov S B 
Published: June 2020

Abstract
The subject of this paper is a constricted electric discharge, generated over a mixing layer of ethylene (as a generic fuel) and carbon dioxide (as a product of combustion) directly injected into a supersonic airflow. The discharge location and plasma parameters are characterized based on optical spectral analysis, fast camera observation, and electrical probe measurements. It is shown that the discharge mostly locates within a zone of gas composition relevant to the mixing layer and drifts toward the core airflow in the case of carbon dioxide or stay in the area rich by secondary gas in the case of ethylene injection. The analysis of the experimental data demonstrates that the discharge behaviour is determined by the balance of thermal dissociation, dissociative thermal conduction and nonequilibrium ionization.
Non-adiabatic transitions in the near-UV photodissociation of

H3+
Authors: Urbain X , Dochain A , Marion R , Launoy T , Loreau J 
Published: June 2020

Synopsis
The near-UV photodissociation of

H
3
+

has been studied in a fast beam experiment. The kinetic energy release and branching ratio among the fragmentation channels were obtained by three-dimensional imaging of the dissociation products. It is found that the photodissociation of vibrationally excited

H
3
+

mostly produces vibrationally cold

H
2
+

and hot H2. The non-adiabatic repopulation of the ground potential energy surface after excitation is accounted for by modelling the wavepacket dynamics on the intersecting potential energy surfaces.
Phase sensitive coherent control excitation schemes applied to photoionization microscopy of the hydrogen atom
Authors: Kalaitzis P , Danakas S , Ferentinou K , Lépine F , Bordas C , Cohen S 
Published: June 2020

Synopsis
Photoionization microscopy (PM) is employed for imaging the flux of slow (meV) electrons ejected via atomic photoionization in the presence of a static electric field. Just above the ionization limit continuum and quasi-disrete states are degenerate. In hydrogen atom resonant excitation dominates over the continuum one, while the reverse holds for more complex atoms. We demonstrate theoretically that by using a bichromatic ω/2ω laser field and by applying phase sensitive coherent control techniques it is possible to unbury and isolate other-wise obscured resonant features in PM images.
Coherent control schemes for the photoionization of helium in the extreme ultraviolet spectral region
Authors: Liu C-N , Morishita T 
Published: June 2020

Synopsis
We present a theoretical study for coherent control based on resonant excitation to doubly excited states of helium. Bichromatic schemes are designed, using XUV light from the seeded free-electron laser FERMI, where the phase of the third harmonic relative to the fundamental can be controlled. In addition to demonstrate the interference effects, we provide detailed theoretical analyses to identify the FEL parameters, such as intensities and pulse durations, needed for experimentally observable coherent control of the photoionization yields.
Attosecond delays in photoionization studied with coherent-controlled FEL
Authors: You D , Ueda K , Tugs O , Orimo Y , Sato T , Ishikawa K L , Gryzlova E V , Staroselskaya E I , Grum-Grzhimailo A N , Carpeggiani P A , Csizmadia T , Füle M , Harshitha N G , Sansone G , Maroju P K , Meyer M , Mazza T , D’Elia A , Callegari C , Di Fraia M , Plekan O , Giannessi L , Allaria E M , De Ninno G , Trovò M , Badano L , Diviacco B , Gauthier D , Mirian N S , Penco G M , Rebernik P R , Spampinati S , Spezzani C , Gaio G , Prince K C 
Published: June 2020

Synopsis
When an electron is ejected from an atom after absorption of a photon, the photoelectron wave packet has an extremely short group delay between the photon absorption and the electron emission. This interval, called the Eisenbud-Wigner-Smith delay, is on the order of a few attoseconds. Here, we present a new method to measure the photoemission delay, using coherent-controlled free-electron laser pulses.
Time-resolved dynamics of thiophene dication – probing parent molecule survival times and multi-step dissociation processes of cyclic molecules by free-electron-laser experiments combined with theoretical simulations
Authors: Kukk E , Fukuzawa H , Nagaya K , Niskanen J , Luo Y , Peschel J , Kooser K , Itl E , Pelimanni E , Saito S , You D , Maclot S , Nizou A , Ha D T , Myllynen H , Ueda K 
Published: June 2020

Synopsis
Thiophene is a cyclic molecule that becomes unstable as a molecular dication. We followed the multi-step dissociation dynamics triggered by soft x-ray FEL pulses from SACLA, core-ionizing the S 2p orbital and creating parent dications by the Auger decay. The time-evolution was probed by optical laser pulsesthat reveal the survival lifetime of the parent dication and the build-up of fragmentation proceeding by ring opening and rupture, accompanied by hydrogen ejection and secondary dissociation. Experimental results are compared to statistical analysis of molecular dynamics simulations.
Ion-ion collision-induced evaporative cooling of atomic and molecular ions by autoresonance in an electrostatic ion beam trap
Authors: Heber O , Gangwar R K , Saha K , Rappaport M L , Zajfman D 
Published: June 2020

Synopsis
A new method for cooling beams of any ion is introduced. The method is autoresonance acceleration of ions inside an Electrostatic Ion Beam Trap. Intrabunch collisions of trapped (molecular) ions transfer energy from the “cold” part of the population of the ion distribution to the “hot” part, which, in turn, evaporates from the bunch. As a result, bunches of ions were cooled from about 45 K to well below 1 K.
Photodetachment of negative ion beams for the ion-neutral merged-beam experiments at RICE
Authors: Iizawa M , Iida S , Kuma S , Azuma T , Nakano Y 
Published: June 2020

Synopsis
Generation of neutral atomic beam is under development for the ion-neutral merged-beam experiment at the RIKEN Cryogenic Electrostatic ion storage ring (RICE). The beam is produced by a photodetachment of a negative ion beam using a high power laser diode array with a wavelength of 808 nm. In order to increase the detachment efficiency, we have developed an optical cavity built with a planar mirror. In this presentation we will present the current status of the neutral atom beam source.
Reaction Microscope experiments with shaped laser pulses
Authors: Farfán D Martínez , Fross P , Kerbstadt S , Mi Y , Camus N , Sun X , Wollenhaupt M , Pfeifer T , Moshammer R 
Published: June 2020

Synopsis
Using a 4f pulse shaper in combination with a Reaction Microscope we performed 800 nm pump-probe experiments with orthogonally polarized pulses on H₂.
On how classical uncertainties might affect the coherence properties of collisions processes, and how to control them
Authors: Barrachina R O , Navarrete F , Ciappina M F 
Published: June 2020

Synopsis
In principle, the quantum coherence properties of any collision experiment should be affected by unavoidable classical uncertainties. However, they seem to produce no observable effect. This mystery can be solved by introducing the concept of “coherence length” which, in addition, provides a way to control and modify the aforementioned quantum properties. Finally, we discuss different methods to achieve a transition between coherent and incoherent collisions, evaluating their strengths and weaknesses.
Approaches for constraining uncertainty and degeneracy in geometry reconstruction of molecules from Coulomb Explosion Imaging data
Authors: Tian K , Ramadhan A , Singh M D , Sanderson J 
Published: June 2020

Synopsis
Starting with simulated OCS molecular data we use two methods to propose a framework for reconstructing geometries, using Coulomb explosion imaging (CEI), for use in the production of molecular movies. The first method is a lookup table, which helps us investigate the existence and nature of multiple solutions to the geometry reconstruction problem and define regions of degeneracy in molecular structure. The second is a new method using nonlinear constrained optimization. We also use this method to investigate the uncertainty in geometry reconstructions as a function of measurement error.
K-shell electron-impact excitation and polarization of x-ray emission of Fe20+ ion
Authors: Zhang J M , Xie L Y , Zhang D H , Jiang J , Wu Z W , Dong C Z 
Published: June 2020

Synopsis
The total and magnetic cross sections for K-shell electron impact excitation (EIE) of Fe20+ have been calculated using the fully relativistic distorted-wave approach. Degrees of linear polarization of x-ray emission following EIE are presented for several stronger 2p→1s transitions, and compared with the values for the same transition lines but from dielectronic recombination process of Fe21+ in the ground state, obvious differences are found that can be employed in diagnosing the formation mechanism of corresponding x-ray lines.
Bayesian atomic structure calculations for collisional problems
Authors: Mendez AMP , Filippo J I Di , Lopez S D , Mitnik D M 
Published: June 2020

Synopsis
The calculations of collisional processes require an accurate description of the target. In general, the atomic structure is obtained through tedious iterations in which a variety of configurations and parameters are chosen to minimize the differences between the numerical and experimental values of the energies and the oscillator strengths. Using a Bayesian machine learning analysis through a Tree–structured Parzen Estimator, we can reproduce the experimental atomic structure with high accuracy. Results for neutral beryllium are presented.
Integral cross sections of the valence-shell excitations of carbonyl sulphide studied by the high-energy electron scattering
Authors: Liu Y-W , Du X-J , Xu Y-C , Zhu L-F 
Published: June 2020

Synopsis
The integral cross sections (ICSs) of the valence-shell excitations of carbonyl sulphide have significant applications in the astronomical observation. Based on the generalized oscillator strengths (GOSs) of these excitations measured by the high-energy electron scattering, the ICSs of the valence-shell excitations of OCS have been determined in a wide energy region from the threshold to 5 keV with the aid of the BE-scaling method.
Resolving and imaging the stereo-configuration of OCS dimers in gas phase
Authors: Yu X , Li X , Yin Z , Wang C , Luo S , Ding D 
Published: June 2020

Synopsis
Polar, non-polar and cross-shaped isomers of OCS dimer are observed and the corresponding structures are resolved using fs laser-induced Coulomb explosion. These three structures are confirmed in the simulations, and demonstrate that the dimer structures can be reconstructed from the measured momenta distributions. Our study will promote the real time imaging the evolution of molecular dimer at fs time scale after excitation and ionization.
Ab initio quantum calculations of collisional effects in molecular spectra
Authors: Jóźwiak H , Thibault F , Stolarczyk N , Wcisńo P 
Published: June 2020

Synopsis
We present the methodology of obtaining the dataset of the beyond-Voigt line-shape parameters for spectroscopic databases from fully ab initio quantum-scattering calculations. It provides not only the pressure broadening and shift coefficients, but also their speed dependencies and the complex Dicke parameter. This approach is based on the calculations of the generalized spectroscopic cross section, resulting from the close-coupling equations solved for a given scattering system. The calculations were validated on accurate experimental spectra of the helium-perturbed hydrogen molecule.
Jahn-Teller effect on the 1t2 orbital electron momentum distribution of Methane
Authors: Niu S S , Shan X , Tang Y G , Liu Z H , Chen X J 
Published: June 2020

Synopsis
We report an experimental study about the Jahn-Teller effect resulted from the ionization of the high-est occupied molecular orbital (HOMO) 1t2 of methane. The difference of the electron momentum distributions for the Jahn-Teller splitting components reveals the strong interaction between electronic and nuclear vibrational motion.
Momentum transfer dependence behavior of the 3 s-1nl autoionization states of argon studied by high-resolution fast electron impact
Authors: Zhu L-F , Du X-J , Liu Y.-W. 
Published: June 2020

Synopsis
Momentum transfer dependence behavior of the autoionization states plays an unique role in understanding the electronic correlation effect. In the present work, the 3s-1nl autoionization states and their peak profiles of argon have been measured at different scattering angles by fast electron impact. The momentum transfer dependence behaviors of the dipole-allowed and dipole-forbidden autoionization states of argon have been elaborated.
Quenching of interstellar carbenes: Interaction of C3H2 with He and H2
Authors: Ben Khalifa M , Sahnoun E , Wiesenfeld L , Khadri F , Hammami K , Dulieu O 
Published: June 2020

Synopsis
C3H2 molecules are ubiquitous in the Galaxy and present important challenges in their chemistry, whether cyclic or linear, and possibly substituted with D. Obtaining theoretical rotational quenching rates by collisions with He and H2 as projectiles is of great importance in order to get quantitative abundance estimates. It is all the more challenging that many rotational lines are excited during the collision, resulting in computationnally very heavy quantum dynamics. The quality of various approximations will be discussed, as well as the quenching rates for astrophysical applications.
Study of electron impact fine-structure excitation and polarization of highly charged tungsten ions
Authors: Shukla N , Shrivastava R 
Published: June 2020

Synopsis
Study of electron-impact excitation of few highly charged tungsten ions viz. Tm-, Er- and Ho-like has been done using relativistic distorted wave theory (RDW). The dipole allowed transitions of these ions are considered and electron-impact excitation cross section are reported in the wide range of energy. These calculated cross section are also fitted with suitable analytical expressions for the direct use in plasma modelling. Further-more, the polarization of the emitted photons on consequent decay of the excited tungsten ions are calculated by utilizing density matrix theory.
To disentangle strong resonant Auger decay lines after the

O1s→3σu*

excitation in O2 molecules
Authors: Ding B , Xu W Q , Nicolas C , Song S , Jiang Y , Patanen M , Nandi S , Xiao Z , Miron C , Liu X J 
Published: June 2020

Synopsis
Atomic features may appear in the Auger electron spectra after an electron is excited from a core orbital to an antibonding orbital in molecules, as a result of complex competitions among electron and nuclear motions. Relatively weak atomic features were widely discussed in spectator Auger decay processes on top of

O
1
s
→
3

σ
u
*

excitation in O2 molecules. Thee strong Auger decay processes are heavily-overlapped in the electron spectrum and not discussed up to now. Here, using multi-particle coincidence setup, we separate these Auger decay processes for the first time.
Auger-like correlations in the two-photon above threshold ionization of atoms and molecules in the vicinity of the giant resonance
Authors: Lagutin B M , Petrov I D , Novikovskiy N M , Sukhorukov V L , Demekhin Ph V , Ehresmann A 
Published: June 2020

Synopsis
The two-photon ionization of the Ne–CH4 and Ar–SH4 isoelectronic systems was studied theoretically for the photon energies exceeding the ionization threshold of the outer shells. The calculations demonstrate that the two-photon ionization of the investigated objects is almost entirely a collective process if the one-photon energy corresponds to the energy of the

n
ℓ
→
ε

ℓ
R
′

giant resonance. The largest contribution to the transition (2) amplitude stems from the Auger-like correlation

n

ℓ
2

→

(
2
)

ε

ℓ
R

′
2

⇒
n
ℓ

ε
″

ℓ
″

.
Multi-electron/ion coincidence spectroscopy in Xe triple ionization
Authors: Khalal M A , Palaudoux J , Lablanquie P , Andric L , Zitnik M , Bucar K , Bizau J-M , Cubaynes D , Penent F 
Published: June 2020

Synopsis
The study of atomic multiple photoionization by a single photon can be performed by detecting in coincidence all the corresponding electrons with a magnetic bottle time of flight spectrometer. To reveal minor triple ionization channels of Xe atom that are hindered by radom coincidences, we have detected three electrons in coincidence with the corresponding Xe3+ ion, thanks to a new permanent magnet design using a drilled soft iron pole.
Strong bond rearrangement and hydrogen-pair emission in linear geometry following water ionization by electron impact
Authors: Ferreira N , Sigaud L , Montenegro E C 
Published: June 2020

Synopsis
The H0 + O+ + H0 fragmentation of water by electron impact is studied using the delayed extraction time-of-flight technique to uncover kinematic attributes of suprathermal O+ ions. It is found that the H0 pair ejections occur under a large angular rearrangement, in an approximate linear geometry, and leaving the O+ near at rest, with ∼50% of the O+ produced in water fragmentation by swift electrons presenting this feature. It is shown that this behavior is closely associated to the excitation of satellites one-electron-two-vacancies states near the 2a1 orbital.
Electron-impact ionization of Fe3+
Authors: Kynienė A , Kučas S , Masys Š , Pakalka S , Jonauskas V 
Published: June 2020

Synopsis
Electron-impact ionization cross sections are studied for levels of the ground and first excited con-figurations of the Fe3+ ion. Convergence for the excitation-autoionization cross sections due to excitations to the high-nl shells is investigated. Single configuration and configuration interaction methods are used in the study. Scaling is applied to the distorted wave cross sections of the excitation-autoionization and collisional ionization processes.
Revisit of (e,2e) & (e,3e) processes on atoms with twisted electron impact
Authors: Dhankhar N , Mandal A , Sebilleau D , Choubisat R 
Published: June 2020

Synopsis
We compute Triple Differential Cross Section (TDCS) and Five-fold Differential Cross Section (FDCS) for (e,2e) & (e,3e) processes on atoms respectively to investigate the effects of non zero angular momentum and the apex angle of the twisted electron. We observed that the differential coincidence cross sections largely depend on these parameters.
The role of multiple ionization in fast highly charged ions collisions on H2O
Authors: Bachi N , Otero G S , Otranto S , Olson R E 
Published: June 2020

Synopsis
An adaptive classical trajectory Monte Carlo model that explicitly considers the eight electrons cor-responding to the valence molecular orbitals of the H2O molecule is introduced. In this dynamical model, the electrons’ binding energies change throughout the collision ensuring the proper energy deposition by the projectile for multiple electron removal. Present results are relevant to the ion-therapy program, specially at irradiation planning stages in which detailed information on the electronic emission spectra are needed as input data.
Photoionization of the open-shell nitrogen atom confined in C60
Authors: Gorczyca T W , Manson S T 
Published: June 2020

Synopsis
Endofullerene photoionization of open-shell N@C60 is investigated using a coupled-channel, correlated R-matrix approach with additional modifications for a finite spherical-shell fullerene potential. Particular focus is on the initial-state dependence of the photoionization cross section. Comparisons show significant differences between the 1s
22s
22p
3(4S) initial state and the metastable 2D and 2P states, as well as strong confinement oscillatory structure.
Plasmon assisted isomerization in naphthalene and azulene
Authors: Vinitha M V , Najeeb P K , Kala A , Bhatt P , Safvan C P , Vig S , Kadhane U 
Published: June 2020

Synopsis
Plasmon excitation in polycyclic aromatic hydrocarbons is a dominant excitation mode in fast charged particle collisions. Excitations of this nature lead to several secondary processes like ejection of neutral atomic or molecular fragments. The present work explores the influence of plasmon excitation on isomerization on two small size PAHs namely, naphthalene and azulene. Moreover, the existence of double plasmon excitation is demonstrated with the help of experimental observations of dication dissociation and plasmon excitation model calculations.
Absolute total cross sections of multiple electron processes for molecules of biological interest by fast proton impact
Authors: Terekhin P N , Quinto M A , Monti J M , Fojón O A , Rivarola R D 
Published: June 2020

Synopsis
We present the study of multiple electron processes produced by impact of proton beams on molecular targets from intermediate to high projectile impact energies. Transition probabilities and absolute cross sections were determined by using the Continuum Distorted Wave-Eikonal Initial State approximation. Results were compared with previous calculations and also with recent experimental data.
Experimental investigation of dissociative ionization of NeAr dimer by electron impact
Authors: Yan S , Ma X , Zhu X L , Zhang S F , Zhao D M 
Published: June 2020

Synopsis
A two body fragmentation experiment of NeAr dimer by 480 eV electron impact was performed. By recon-structing the momenta of Ne+ ion, Ar+ ion and one electron, the 2D coincidence map between Kinetic energy release and electron energy is obtained, from which two islands are observed. It is found that, Interatomic Coulombic Decays induced by Ne+Ar ion and Ar+ Ne ion can both take place in our experiment, as well as Radiative Charge Transfer. This is different from X ray in which only one decay process is dominant in one incident energy.
Target sensitivity of photoelectron holograms
Authors: Borbély S , Tóth A , Zs Kiss G , Nagy L 
Published: June 2020

Synopsis
Photoelectron holograms appear as a modulation in the momentum distribution of the photoelectrons created during the ionization of atomic and molecular targets by few-cycle laser pulses, and it is the direct result of the continuum electonic wave packet scattering on the target. Using first principle calculations we show that the pattern of the formed photoelectron hologram is strongly influenced by the shape of the target’s binding potential.
Shrinking diffraction “fringes” in positronium formation from C60 to C240
Authors: Hervieux P –A , Chakraborty A R , Chakraborty H S 
Published: June 2020

Synopsis
Due to the bulk electron capture from the molecular shell of fullerenes by incoming positron projectiles and a dephasing effect across the shell width, the positronium formation signal yields diffraction fringes in the target recoil momentum space. Our results show the variance in the separation and shape of the fringe pattern as a function of the fullerene size from C60 to larger C240.
State-selective single electron capture in slow O
6+-He collisions
Authors: Xu J W , Zhu X L , Feng W T , Zhao D M , Zhang S F , Guo D L , Gao Y , Ma X 
Published: June 2020

Synopsis
The state-selective single-electron capture processes were measured by cold-target recoil-ion momentum spectroscopy in O
6+-He collisions between 18keV and 96keV. From the longitudinal momentum spectrum of recoil ions, the single electron captured into n=3 states of projectile ion is predominant and n=4 states have a small contribution. The oscillation structure of angular differential cross sections was observed. The present experimental results are compared with other experiments at low energy and the predictions of the molecular Columbic barrier model.