Advances in atomic physics

In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics

Opacity Corrections for Resonance Silver Lines in Nano-Material Laser-Induced Plasma

Q-switched laser radiation at wavelengths of 355, 532, and 1064 nm from a Nd: YAG laser was used to generate plasma in laboratory air at the target surface made of nano-silver particles of size 95 ± 10 nm. The emitted resonance spectra from the neutral silver at wavelengths of 327.9 nm and 338.2 nm indicate existence of self-reversal in addition to plasma self-absorption. Both lines were identified in emission spectra at different laser irradiation wavelengths with characteristic dips at the un-shifted central wavelengths. These dips are usually associated with self-reversal. Under similar conditions, plasmas at the corresponding bulk silver target were generated. The recorded emission spectra were compared to those obtained from the nano-material target. The comparisons confirm existence of self-reversal of resonance lines that emerge from plasmas produced at nano-material targets. This work suggests a method for recovery of the spectral line shapes and discusses practical examples. In addition, subsidiary calibration efforts that utilize the Balmer series Hα-line reveal that other Ag I lines at 827.35 nm and 768.7 nm are optically thin under variety of experimental conditions and are well-suited as reference lines for measurement of the laser plasma electron density

Laser gain calculations for soft X-ray and XUV radiation emitted from copper like ions by electron collisional pumping

Electron impact excitation rate coefficients, Level population densities and gain coefficients for six excited ions with Z = 51, 52, 53, 54, 55, 56 in the copper isoelectronic sequence have been calculated. The electron collisional excitation rate coefficients are calculated according to the analytical formulas of Vriens and Smeets. Fine structure energy levels, transition probabilities and oscillator strengths needed in the calculations have been calculated using Cowan atomic structure code with relativistic corrections for [Ar]3d10nl with n = 4-7 and l = 0-6. The level population densities are calculated by solving the coupled rate equations involving 30 levels. Positive gain coefficients of the possible emitted lines are obtained at three selected electron temperatures namely 1/4, 1/2 and 3/4 of the ionization energy. The present calculated data show promising values for the production of soft X-ray and XUV laser by collisional pumping for the transitions 5p-5s and 6d-5f with wavelengths between 108 Å and 571 Å. The values of the maximum gain coefficient are found to increase with atomic number and their order of magnitude ranges from102 cm-1 to 104 cm−1.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Magnetic quadrupole (M2) X-ray laser transitions from neon like arsenic As+23

Neon-like arsenic As+23 are studied theoretically where 457 energy levels are calculated. A highly energetic electrons are considered as the main pumping source for the population of the energy levels. Relativistic calculations are considered through the calculations and the possible X-ray laser transitions are determined with their gain coefficients. The soft X-ray laser transitions (Îť â 17-27 nm) are dominant by the magnetic quadrupole M2. The results show good agreement with the observed data and moreover, new transitions that are not given in literatures are calculated together with their gain values.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Thermodynamic properties of a rotating Bose-Einstein condensation in a harmonic plus quartic trap

In this paper, the thermodynamic properties of a rotating Bose-Einstein condensate confined in a harmonic plus quartic potential are calculated using a modified semiclassical approximation. We determined the condensate fraction, critical temperature and heat capacity of the condensate using a method that takes into account deviations from ideal gas behavior due to the effect of finite size and the chemical potential when it is equal to the ground state energy (positive chemical potential). Predictions that can be directly compared with experiment have been found