• A. A. Mihajlov

      Articles written in Journal of Astrophysics and Astronomy

    • Dynamics Resonances in Atomic States of Astrophysical Relevance

      K. N. Arefieff K. Miculis N. N. Bezuglov M. S. Dimitrijević A. N. Klyucharev A. A. Mihajlov V. A. Srećković

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      Ionized geocosmic media parameters in a thermal and a subthermal range of energy have a number of unique features. The photoresonance plasma that is formed by optical excitation of the lowest excited (resonance) atomic states is one example of conversion of radiation energy into electrical one. Since spontaneous fluorescence of excited atoms is probabilistic, the description of the radiating quantized system evolution along with photon energy transfer in a cold atom medium, should include elements of stochastic dynamics. Finally, the chaotic dynamics of a weakly bound Rydberg electron over a grid of the energy level diagram of a quasi-molecular Rydberg complex provides an excitation migration of the electron forward to the ionization continuum. This work aims at discussing the specific features of the dynamic resonances formalism in the description of processes involving Rydberg states of an excited atom, including features in the fluorescence spectrum partially caused by the quantum defect control due to the presence of statistic electromagnetic fields.

    • Non-Elastic Processes in Atom Rydberg-Atom Collisions: Review of State of Art and Problems

      A. A. Mihajlov V. A. Srećković Lj. M. Ignjatović A. N. Klyucharev M. S. Dimitrijević N. M. Sakan

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      Inour previous research, it has been demonstrated that inelastic processes in atom Rydberg-atom collisions, such as chemi-ionization and ($n-n'$) mixing, should be considered together. Here we will review the present state-of-the-art and the actual problems. In this context, we will consider the influence of the ($n-n'$)-mixing during a symmetric atom Rydberg-atom collision processes on the intensity of chemi-ionization process. It will be taken into account H(1s) + H*(𝑛) collisional systems, where the principal quantum number is $n \gg 1$. It will be demonstrated that the inclusion of ($n-n'$) mixing in the calculation, influences significantly on the values of chemi-ionization rate coefficients, particularly in the lower part of the block of the Rydberg states. Different possible channels of the ($n-n'$)-mixing influence on chemi-ionization rate coefficients will be demonstrated. The possibility of interpretation of the ($n-n'$)-mixing influence will be considered on the basis of two existing methods for describing the inelastic processes in symmetrical atom Rydberg-atom collisions.

    • Inverse Bremsstrahlung in Astrophysical Plasmas: The Absorption Coefficients and Gaunt Factors

      A. A. Mihajlov V. A. Srećković N. M. Sakan

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      The electron–ion inverse Bremsstrahlung is considered here as a factor of the influence on the opacity of the different stellar atmospheres and other astrophysical plasmas. It is shown that this process can be successfully described in the frames of cut-off Coulomb potential model within the regions of the electron densities and temperatures. The relevant quantum mechanical method of the calculation of the corresponding spectral coefficient processes is described and discussed. The results obtained for the plasmas with the electron densities from 1014 cm$^{-3}$ to 2 · 1019 cm$^{−3}$ and temperatures from 5 · 103 K to 3 · 104 K in the wavelength region 100 nm < 𝜆 < 3000 nm are presented. Also, these results can be of interest for different laboratory plasmas.

    • MOL-D: A Collisional Database and Web Service within the Virtual Atomic and Molecular Data Center

      V. Vujčić D. Jevremović A. A. Mihajlov Lj. M. Ignjatović V. A. Srećković M. S. Dimitrijević M. Malović

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      MOL-D database is a collection of cross-sections and rate coefficients for specific collisional processes and a web service within the Serbian Virtual Observatory (SerVO) and the Virtual Atomic and Molecular Data Center (VAMDC). This database contains photo-dissociation cross-sections for the individual ro-vibrational states of the diatomic molecular ions and rate coefficients for the atom-Rydberg atom chemiionization and inverse electron–ion–atom chemi-recombination processes. At the moment it contains data for photodissociation crosssections of hydrogen H+2 and helium H+2 molecular ions and the corresponding averaged thermal photodissociation cross-sections. The ro-vibrational energy states and the corresponding dipole matrix elements are provided as well. Hydrogen and helium molecular ion data are important for calculation of solar and stellar atmosphere models and for radiative transport, as well as for kinetics of other astrophysical and laboratory plasma (i.e. early Universe).

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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