544 Results Found

The atomic structure of californium is probed by two-step resonance ionization spectroscopy. Using samples with a total amount of about $2\times {10}^{10}$ Cf atoms (ca. 8.3 pg), ground-state transitions as well as transitions to high-lying Rydberg states a...

The strong-field approximation (SFA) has been widely applied in the literature to model the ionization of atoms and molecules by intense laser pulses. A recent re-formulation of the SFA in terms of partial waves and spherical tensor operators helped...

In this paper, a novel ionization energy, $IE$, set theory-based organizational structure is suggested: (i) iso-protonic sets, ${}_{Z}IE$; (ii) iso-electronic sets, $I{E}_s$; and (iii) iso-ionic sets, $I{E}^{i+}$. A computational algorithm is proposed which was demonstra...

Amusia and Kheifets in 1984 introduced a Green’s function formalism to describe the effect of many-electron correlation on the ionization spectra of atoms. Here, we exploit this formalism to model the shake-off (SO) process, leading to the non-...

Accurate ionization energies are essential for understanding the electronic structures of atoms and molecules and benchmarking quantum-chemical methods. We report the calculated ionization energies of the H, C, N, O, F, P, and S atoms using several q...

We experimentally studied the Rydberg level shift caused by the electric field, which is generated by Rydberg atom collision induced ionization in a cesium atomic ensemble. The density of charged particles caused by collisions between Rydberg atoms i...

Highly-ionized atoms with special properties have been proposed for interesting applications, including potential candidates for a new generation of optical atomic clocks at the one part in 10¹⁹ level of precision, quantum information processing and...

For the control of fusion reactors, we need to accurately know all the possible reactions and collisional cross sections. Although large-scale trials have been performed over the last decades to obtain this data, many basic atomic and molecular cross...

The dichroism effects, i.e., asymmetries of the ionization probability with respect to the inversion of either the atomic orientation (magnetic dichroism, MD) or the circular polarization degree of the photon beam (circular dichroism, CD), are invest...

Relativistic triple differential cross-sections (TDCS) for ionization of hydrogen atoms by positron impact have been calculated in the symmetric coplanar geometry. We have used Dirac wave functions to describe free electron’s and positron’s sates. Th...

Chemical mechanical planarization (CMP) is frequently used in semiconductor manufacturing to polish the surfaces of multiple layers in a wafer. The CMP uses a slurry that aids in fabricating a smooth surface by removing the excess materials. However,...

The time-dependent close-coupling method has been recently applied to calculate electron-impact direct ionization cross sections for the Kr, W, and Pb atoms. An overview is presented for these three heavy neutral atom systems. When the direct ionizat...

Electron-impact ionization (EII) processes are essential for modelling high-temperature plasma in quite different research areas, from astrophysics to material science to plasma and fusion research and in several places elsewhere. In most, if not all...

By numerically solving the time-dependent Schrödinger equation (TDSE), we study the elementary excitation and ionization processes of atomic hydrogen on the same footing, which is irradiated by the two-color laser fields composed of a strong 400...

A complete form of the post version of the continuum distorted wave (CDW) theory is used to investigate the single ionization of multielectronic atoms by fast bare heavy ion beams. The influence of the non-ionized electrons on the dynamic evolution i...

The paper presents an analysis of data on the cross sections of electron impact ionization of atoms of alkali metals, hydrogen, noble gases, some transition metals and Al, Fe, Ni, W, Au, Hg, U. For the selected sets of experimental and theoretical da...

The present paper revisits the determination of the semi-classical limit of the Feshbach resonances which play a role in electron impact broadening (the so-called “Stark“ broadening) of isolated spectral lines of ionized atoms. The Gailitis approxima...

We present an efficient numerical method to solve the time-dependent Schrödinger equation in the single-active electron picture for atoms interacting with intense optical laser fields. Our approach is based on a non-uniform radial grid with smoo...

We present a theoretical study focused on the photoelectron spectrum of near-infrared (NIR) laser-driven ionization of hydrogen atoms by attosecond pulse trains composed of several HHs of the former. We analyze the effects of increasing the intensity...

Photoelectron angular distributions of the two-photon ionization of neutral atoms are theoretically investigated. Numerical calculations of two-photon ionization cross sections and asymmetry parameters are carried out within the independent-particle...

We investigate ionization of atomic hydrogen by electron- and positron-impact. We apply the Coulomb–Born (CB1) approximation, various modified CB1 approximations, the three body distorted wave (3DW) approximation, and the time-dependent close-couplin...

For many disciplines of science, all conceivable collisional cross-sections and reactions must be precisely known. Although recent decades have seen a trial of large-scale research to obtain such data, many essential atomic and molecular cross-sectio...

This paper presents an analysis of data on the cross sections of elastic and inelastic collisions of electrons with noble gases, alkali and other atoms. For the selected sets of experimental and theoretical data, optimal analytical formulas are found...

The single-center convergent close-coupling (CCC) method is applied to calculate positron scattering from boron. A model potential approach is utilized to extract the positronium formation, direct ionization, and values between the positronium format...

In this paper we suggest Penning ionization as an important route of formation for ionic species in upper planetary atmospheres. Our goal is to provide relevant tools to researchers working on kinetic models of atmospheric interest, in order to inclu...

The L-subshell ionization cross sections and total L–X-ray production cross sections for the Ag atom by the electron impact near the ionization threshold were calculated with a classical-trajectory Monte Carlo method. The results were compared...

In the present paper, the correction of the recombination and ionization processes of the hydrogen atom due to the thermal interaction of two charges was considered. The evaluation was based on a rigorous quantum electrodynamic (QED) approach within...

Pauling introduced the concept of electronegativity of an atom which has played an important role in understanding the polarity and ionic character of bonds between atoms. We set out to define a related concept of atomic reactivity in such a way that...

Electron configurations are known to provide valuable insights into the electronic structure and behavior of atoms. They specify which and how the electronic (sub-) shells are occupied, and are thus an essential ingredient for most atomic observables...

The spatial distribution of the hydrogen atom density was evaluated in a spherical tokamak (ST) plasma sustained only with 28 GHz electron cyclotron heating (ECH). The radially resolved H_δ emissivity was measured using multiple viewing chord sp...

In the present paper, we revisit the determination of Feshbach resonances in the elastic and fine-structure cross-sections of the spectral lines of ionized atoms colliding with electrons. The Gailitis approximation will be recalled and used to calcul...

This paper proposes a new double-nozzle technique for in-gas-jet laser resonance ionization spectroscopy. We explored the functionality of this new technique through detailed gas dynamic and Monte Carlo atom-trajectory simulations, in which results a...

Population models are a prerequisite for performing qualitative analysis of population densities measured in plasmas or predicting the dependence of plasma emission on parameter variations. Models for atomic helium and hydrogen as well as molecular h...

We performed a fully differential experimental and theoretical study on ionization of He in intermediate-energy collisions with protons for a small projectile coherence length. Data were taken for an ejected electron energy corresponding to a speed c...

When charged particles collide with atoms, atomic inner shell electrons become ionized, producing characteristic X-rays. This phenomenon is called particle-induced X-ray emission (PIXE). The characteristic X-ray production cross-sections from PIXE ar...

RAdiation-Detected Resonance Ionization Spectroscopy (RADRIS) is a versatile method for highly sensitive laser spectroscopy studies of the heaviest actinides. Most of these nuclides need to be produced at accelerator facilities in fusion-evaporation...

The interaction of ionizing photons with atoms or ions is a fundamental process in nature, with laboratory, atmospheric and astrophysical implications [...]

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS....

We report triple differential cross-sections (TDCSs) for the electron impact single ionization of tungsten atoms for the ionization taking place from the outer sub shells of tungsten atoms, viz. W (6s), W (5d), W (5p) and W (4f). The study of the ele...

Using measured cross-sections and polarizability data, an empirical scaling law is extracted for the electron collision single-ionization cross-section maxima of neutral atoms. We found that the cross sections scale linearly with the target’s s...

The Coulomb-dipole theory of positron vs. electron impact ionization of hydrogen (as a proxy for neutral atoms) is reviewed, emphasizing how the analytic form of the threshold law (but not the magnitude) can be the same, whereas the physics of each i...

A kinetic scheme for non-equilibrium regimes of atmospheric pressure air discharges is developed. A distinctive feature of this model is that it includes associative ionization with the participation of N(²D, ²P) atoms. The thermal dissociation of vi...

The interaction between two ground state hydrogen atoms in a collision was studied using the four-body classical trajectory Monte Carlo method. We present the total cross sections for the dominant channels, namely for the single ionization of the tar...

A model of a stationary glow-type discharge in atmospheric-pressure air operated in high-gas-temperature regimes (1000 K < T_g < 6000 K), with a focus on the role of associative ionization reactions involving N(²D,²P)-excited atoms, is developed...

Sequential two-photon ionization is a process that is experimentally accessible due to the use of new free-electron laser sources for excitation. For the prototypical rare Ar gas atoms, a photoelectron spectrum (PES) corresponding to the second step...

Electron removal (target ionization and/or projectile electron loss) in neutral–atom collisions is theoretically studied for the impact of H${}^0$, He${}^0$ and He${}^{+}$ beams on noble gases (He, Ne and Ar). These reactions are investigated theoretically with...

We study the Rabi flopping of the population between the ground and excited 2p states of the hydrogen atom, induced by intense short laser pulses of different shapes and of carrier frequency $\omega =0.375$ a.u. which resonantly couples the two states,...

The article is devoted to a brief description of the ATOM computer program system, designed to study the structure, transition probabilities and cross sections of various processes in multielectron atoms. The theoretical study was based on the concep...

The present investigation reports on the extended study of the third spectrum of indium (In III). This spectrum was previously analyzed in many articles, but, nevertheless, this study represents a significant extension of the previous analyses. The m...

The generation of highly charged ions in laser plasmas is usually associated with collisional ionization processes that occur in electron–ion collisions. An alternative ionization channel caused by tunnel ionization in an optical field is also...