Revealing the Target Electronic Structure with Under-Threshold RABBIITT

The process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) reveals the target atom electronic structure when one of the transitions proceeds from below the ionization threshold. Such an under-threshold RABBITT resonates with the target bound states and thus maps faithfully the discrete energy levels and the corresponding oscillator strengths. We demonstrate this sensitivity by considering the Ne atom driven by the combination of the XUV and IR pulses at the fundmanetal laser frequency in the 800 and 1000 nm ranges.

Study of the Dressed State of Hydrogen Atom in Electron Atom Elastic Collision in Laser Field

We discuss the various important aspects of the theory of electron-atom elastic collision in laser field. We analyze the collision accompanied by the transfer of photons. We study the free electron states i.e. Volkov states and target atomic states i.e. Dressed states. We calculate the first-Born scattering matrix for electron-atom elastic collision. The present work accounts the calculation for hydrogen as target atom in soft photon limits i.e., in weak field. The dressing effect becomes significant in the region of low momentum transfer, reaches maximum of value of 25000 a.u. at momentum transfer of 0.44. This work explains that the differential cross-section does not occur very low and at very high momentum transfer. However, it occurs at moderate momentum transfer.

Experimental study on electron detachment cross sections of Cl– in collisions with inert gas atoms

The single-electron and double-electron detachment cross sections of Cl– in collision with inert gas atoms (He–Xe) have been measured by the growth rate method. The incident negative ions’ energies are from 5 to 30 keV. It is found that the single-electron detachment cross sections become greater and greater when the target atoms change from helium to xenon. However, double-electron detachment cross sections show a more complicated relationship with the target atom changing. The results of this work have been compared with the previous data, and a model based on energy division is used to interpret the trends of cross sections.

Laser-Assisted (e, 2e) Collisions in the Symmetric/Asymmetric Coplanar Geometry

In this review, we present a comprehensive survey of laser-assisted (e, 2e) reactions. The influence of a laser field on the dynamics of (e, 2e) collisions in atomic hydrogen is analyzed in the symmetric and asymmetric coplanar geometries. Particular attention is devoted to the construction of the dressed (laser-modified) target wave functions, in both the initial and final states. The calculation is performed in the framework of Coulomb-Volkov-Born approximation, where the initial and final electrons are described by Volkov wave functions, while the interaction of the incident electron with the target atom is treated in the first and the second Born approximation. The state of the ejected electron is described by a Volkov/Coulomb-Volkov wave function. A detailed account is also given of the techniques we have used to evaluate the scattering amplitudes. The influence of the laser parameters (frequency, intensity, and direction of polarization) on the angular distribution of the ejected electron is discussed, and a number of illustrative examples are given. The structure of the triple differential cross section in the vicinity of resonances is also analyzed.

Вероятность процессов захвата электронов у атомов аргона ионами -=SUP=-3-=/SUP=-Не-=SUP=-2+-=/SUP=- при различных параметрах удара

We have measured the absolute values of total cross sections of capture of one and two electrons by He^2+ ions from argon atoms. The differential scattering cross sections have been determined for fast atoms and singly charged helium ions formed in each of these processes (without and with additional ionization of the formed slow argon ion). Measurements have been taken for He^2+ ions with kinetic energy of 6 keV in scattering angle range 0–2.5°. Based on the measured differential cross sections using different model atomic particle interaction potentials, we have calculated the cross sections of these processes as functions of the impact parameter. The probabilities of realization of these processes with electron density distribution in different shells in the target atom have been compared. The applicability of the expressions for the screened Coulomb interaction potentials in the description of scattering of particles that have captured electrons has been demonstrated.

A study of the 160 MeV Ni7+swift heavy ion irradiation effect of defect creation and shifting of the phonon modes on MnxZn1–xO thin films

The energy loss to vacancy production shows that the number of vacancies depend on the displacement energy assigned to each target atom element is shown separately.

Proton and antiproton impact excitation of H(2s) atom

Direct excitations for atomic hydrogen 2s → 3s, 3p, and 3d transitions by proton and antiproton collisions have been investigated by using an impact parameter treatment. The calculations are performed within the impact parameter versions of the first- and second-order Born approximations, as well as the solution of the coupled differential equations arising from the one-center atomic-orbital close-coupling approach. We have considered calculations that allow couplings to the n = 1–5 states (up to g sub-levels) of the target atom as well as others that neglect the effect of all states other than the initial and final states of the target atom. The sensitivity of the cross sections to the sign of the projectile charge as well as the influence of the mechanism of possible electronic transitions allowed by the techniques under consideration have been studied. The calculated cross sections are compared with those obtained by previous calculations.

Influence of electron motion in target atom on stopping power for low-energetic ions

In this paper the stopping power was calculated, representing the electrons of the target atom as an assembly of quantum oscillators. It was considered that the electrons in the atoms have some velocity before interaction with the projectile, which is the main contribution of this paper. The influence of electron velocity on stopping power for different projectiles and targets was investigated. It was found that the velocity of the electron stopping power has the greatest influence at low energies of the projectile.