A Fabry–Perot interferometry was used to measure with a precision of about (10^{-4}) the Landé factor values of the levels issued from the 5s5p, 5s6d, 5s6s and 5s7p configurations of cadmium. Fully relativistic MCDHF calculations taking into account Breit and QED effects were performed to interpret the results of the experiment performed on the cadmium isotope 114. In addition to the four experimental Landé (g_J) values, new theoretical results for 12 levels are reported for the first time.
The formation and temporal evolution of the plasma boundary layer in plasma immersion ion implantation is investigated in the presence of a magnetic field. It is assumed that the ions are thermalized. When a high-voltage pulse with a ramp function is applied to a target immersed in plasma, a positive space charge is formed and expanded around it. The rise time of the ramp function of the pulse voltage influences the formation and expansion of the plasma boundary layer near the target. The time evolution of the ion current density, ion kinetic energy and ion incident angle as well as the time evolution of the positive space charge and the boundary layer thickness are studied as a functions of the magnetic field, neutral gas pressure and rise time of the ramp function. Our findings show that the time dependency of the variables of the plasma boundary layer is more pronounced for a longer rise time.
The governing equations, the simulation zone and temporal behavior of the incident angle of the ion for different magnetization parameters, neutral gas pressure and rise time
In this study, we employed an atmospheric-pressure non-thermal plasma jet that used silver nitrate solution as the precursor which is injected, in an aerosol state, into the plasma jet to create silver nanoparticles with the desired distribution on the glass substrate. The crystal structure and morphology of the Ag nanoparticles printed on the glass substrate were characterized by X-ray diffraction (XRD), the field emission scanning electron microscope (FESEM), and the atomic force microscope (AFM). The XRD patterns confirm Ag nanostructure deposition on the glass. FESEM results show that Ag nanoparticles’ are almost spherical in shape and by increasing the applied voltages, the Ag nanoparticles' size and density increases, and AFM images confirm the results of FESEM images. Rhodamine B with various concentrations was employed to determine the surface-enhanced Raman scattering (SERS) performance of Ag nanoparticles printed on the glass. It shows high sensitivity for Ag layers created by plasma to a threshold that even for the lower concentrations of 10−10M, Rhodamine B is still detectable. There was the optimum SERS effect at a 7 kV voltage. Also, the plasma-printed Ag layers are able to detect methylene blue, usually used as a fungicide in fish ponds and aquariums, even in low concentrations of 10−9M. The residual sulfur dioxide (SO2) of raisins was detected using a plasma-printed silver layer. This shows the application of this plasma-printed silver layer for residual SO2 detection in the food industry.
We report in this work the numerical study of the supercontinuum phenomenon raised from Airy pulses within a silicon-on-insulator waveguide including loss effects, third-harmonic generation (THG) and negative-frequency Kerr (NFK) terms. This study is conducted through a modeling based on the full unidirectional pulse propagation equation model which allows to assume the existence of the NFK term in the Kerr nonlinearity with a spectral filtering. The various effects of the linear loss, the free-carrier absorption/ free-carrier dispersion, the two-photon absorption, the THG, the NFK, the peak power, the pulse duration and the pulse shape are explored.
The Virtual Atomic and Molecular Data Centre (VAMDC) is a distributed infrastructure combining heterogeneous atomic and molecular (A &M) data from more than 41 autonomous databases. In this paper, we present the Species Database, a scientific web service which is a central catalogue providing a useful information on A &M species from all the VAMDC databases. The Species Database is one the key pillars in the technical architecture of the VAMDC, and from the user’s point of view, it is the service to simply and immediately answer the question: Does VAMDC have data on my molecule/atom of interest? This work is structured as follows: After recalling the aims and needs that led to the construction of the Species Database, we will describe how it works, with increasing levels of complexity. First, we will describe how any user, even those with no knowledge of VAMDC, can easily use the dedicated web interface to search for and extract information. Then we will describe an API that more advanced users can use to interact with the Species Database in a more programmatic way. Two appendices cover some technical aspects that are not necessary for using the Species Database, but which may be of interest to readers wishing to understand implementation details and low-level technical subtleties.
We describe the implementation of the current Flexible Atomic Code (FAC) unique electron central potential within the autostructure code. We show that the two codes then give the same atomic data for all practical application purposes. However, autostructure has more flexible potential options which can lead to a more accurate description of atomic processes, especially in low-charged ions.
Energy levels, transition rates, and electron-impact ionization and excitation cross sections for W I are calculated by multi-configuration Dirac–Fock (MCDF) method using the MDFGME code which aims at improving the accuracies of the atomic data which has been crucial for spectroscopic diagnostics of erosion rate of W in plasma surface interaction. Particular attention has been paid to the core–core (CC) and core–valence (CV) electron correlation effects on the level energies and radiative transition rates. The inclusion of the CC and CV electron correlations significantly improves an agreement with the atomic structure data based on experiments. The electron-impact ionization and excitation cross sections are obtained employing binary-encounter Bethe model and scaled plane wave Born approximation, respectively, from the wave functions by the MCDF calculation The obtained collision cross sections and rate coefficients are compared with other available data, which has been used to determine the erosion rate of W with spectral lines in the range of 400–525 nm.
Mixing helium and argon as the working gas of cold plasma jet is expected to combine the merits of He plasma jet and Ar plasma jet and has great potential for medical applications. For this reason, the discharge characteristics and reactive species diagnosis of a He + Ar + O2 plasma jet were studied in this paper. The result shows that the Penning effect between He and Ar is strongest when the volume fraction of Ar in the working gas is 10%, and the plasma jet propagates the longest distance. A low drive voltage and a wide pulse width will weaken the Penning effect between He and Ar, resulting in a decrease in the ionization efficiency of the plasma jet. Gelatin gel was used as the model human tissue, and the effective treatment area of He + Ar + O2 plasma jet on the model tissue increases with the volume fraction of Ar in the working gas. When the volume fraction of Ar is 50%, the effective treatment area of He + Ar + O2 plasma jet is 9 times that of He + O2 plasma jet, and the surface distribution of reactive oxygen species on the model tissue is almost uniform. Moreover, with the increase of volume fraction of Ar, the influence of the change of the plasma jet treatment angle on the surface distribution of reactive oxygen species is significantly weakened, indicating that He + Ar + O2 plasma jet can precisely control the reactive species dosage on the living tissue for clinical application.
Surface distributions of ROS on the model tissue treated by the He + Ar + O2 plasma jet under various argon volume fractions and treatment angles
The He({^+})–He collisions are treated with a three-electron atomic-orbital close-coupling method at intermediate energies. The cross sections are shown for single-electron capture, target excitation, projectile excitation, and target ionization. The results are overall in good agreement with experimental data and previous theoretical results. The minima in the cross sections for target excitation to (2{^1}S) and (2{^1}P) around 20 keV/u are also discussed.
Metastable levels of highly charged ions that can only decay via highly forbidden transitions can have a significant effect on the properties of high temperature plasmas. For example, the highly forbidden 3d(^{10}) (_{J=0}) - 3d(^9)4 s ((frac{5}{2},frac{1}{2})_{J=3}) magnetic octupole (M3) transition in nickel-like ions can result in a large metastable population of its upper level which can then be ionized by electrons of energies below the ground state ionization potential. We present a method to study metastable electronic states in highly charged ions that decay by x-ray emission in electron beam ion traps (EBIT). The time evolution of the emission intensity can be used to study the parameters of ionization balance dynamics and the lifetime of metastable states. The temporal and energy resolution of a new transition-edge sensor microcalorimeter array enables these studies at the National Institute of Standards and Technology EBIT.
NOMAD calculated time evolution of the ratio of the Ni-like and Co-like lines in Nd at varying electron densities compared with measured ratios
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