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Yu. V. Ralchenko

Publications and source records attributed to Yu. V. Ralchenko.

6 recordsLinked to original sources
arXiv2003

Electron-impact broadening of the 3s-3p lines in low-Z Li-like ions

The collisional electron-impact line widths of the 3s-3p transitions in Li-like ions from B III to Ne VIII are calculated with the convergent close-coupling (CCC) method from the atomic collision theory. The elastic and inelastic contributions to the line broadening and their Z-scaling are discussed in detail, and comparisons with recent experimental and theoretical results are also presented. It is found that similar to our previous study of line broadening in Be-like ions, the difference between experimental and CCC results monotonically increases with the spectroscopic charge of an ion.

physics.atom-ph↗
arXiv2001

Accelerated Recombination due to Resonant Deexcitation of Metastable States

In a recombining plasma the metastable states are known to accumulate population thereby slowing down the recombination process. We show that an account of the doubly-excited autoionizing states, formed due to collisional recombination of metastable ions, results in a significant acceleration of recombination. A fully time-dependent collisional-radiative (CR) modeling for stripped ions of carbon recombining in a cold dense plasma demonstrates an order of magnitude faster recombination of He-like ions. The CR model used in calculations is discussed in detail.

physics.plasm-ph↗
arXiv2000

Spectroscopic investigations of a dielectric-surface-discharge plasma source

Spectroscopic investigations of the properties of a plasma produced by a flashboard plasma source, commonly used in pulsed plasma experiments, are presented. The plasma is used to prefill a planar 0.4-ms-conduction time plasma opening switch (POS). A novel gas-doping technique and a secondary surface flashover plasma source are used to locally dope the plasma with gaseous and solid materials, respectively, allowing for spatially-resolved measurements. The electron density, temperature, and plasma composition are determined from spectral line intensities and line profiles. Detailed collisional-radiative modeling is used to analyze the observed line intensities. The propagation velocity and divergence angle of various ions are determined from time-of-flight measurements and Doppler broadening of spectral lines, respectively. This allows for distinguishing the secondary plasma ejected from the POS electrodes from the plasma of the flashboard source.

physics.plasm-ph↗
arXiv1996

Electron Impact Excitation Cross Sections for Hydrogen-Like Ions

We present cross sections for electron-impact-induced transitions n --> n' in hydrogen-like ions C 5+, Ne 9+, Al 12+, and Ar 17+. The cross sections are computed by Coulomb-Born with exchange and normalization (CBE) method for all transitions with n < n' < 7 and by convergent close-coupling (CCC) method for transitions with n < n' < 5 in C 5+ and Al 12+. Cross sections 1s --> 2s and 1s --> 2p are presented as well. The CCC and CBE cross sections agree to better than 10% with each other and with earlier close-coupling results (available for transition 1 --> 2 only). Analytical expression for n --> n' cross sections and semiempirical formulae are discussed.

atom-ph↗
arXiv1995

2-2 and 2-3 Intercombination Transitions in Be-like Ions

We report here on calculation of probabilities of intercombination transitions $2s^2$ $^1S_0$ - $2s2p$ $^3P_1$, $2s3p$ $^3P_1$ for Be-like ions along the isoelectronic sequence for large range of $Z$. Our results obtained with the $1/Z$ expansion method agree well with experimental data including the recent ones.

atom-ph↗