The role of (n-n')-mixing processes in active galactic nuclei broadline region (BLR) clouds has been studied. Our investigation indicates that these collisional processes must have influence on the populations of the excited hydrogen atoms in moderately ionized layers of dense parts of the BLR clouds and are of interest for its modelling and research. We provide results potentially important for the spectroscopy and modeling of the BLR clouds, as well as for the study of hydrogen Rydberg states.

Opacities of the solar and stellar atmospheres are caused by a large number of radiative processes. Within development of more sophisticated stellar atmosphere models, we can further investigate known processes and include all processes not considered before. We calculate the average cross-section and rate coefficients for the photodissociation of the alkali molecular ions Li-2(+), Na-2(+) and LiNa+ ready for further use with a particular accent to the applications for astro plasma research and low temperature laboratory plasma research.

In this paper, the importance of H*(n) + H(1s) collisional ionization as well as the influence of inverse recombination processes in different environments has been investigated within the regions 2 <= n <= 20 and 4 000 K <= T <= 20 000 K. The interpretation of this influence is based on existing method of describing inelastic processes in symmetrical atomRydberg-atom collisions. These processes have effect on ionization and the populations of hydrogen excited atoms in moderately ionized plasma layers. From the results it follows that the investigation of these processes is of interest for the research and modelling of such medium.

The rate coefficients for the chemi-ionization (CI) processes in Na* (n) + Na, Li* (n) + Na, Li* (n) + Li and H* (n) + Li collisions are calculated for wide region of temperatures and the principal quantum numbers. The presented values of the rate coefficients are very useful for the improvement of modelling and analysis of different layers of weakly ionized plasmas in atmospheres of various stars where these and other CI processes could be important and could change the optical characteristics. Also, the results are of interest in spectroscopy of low temperature laboratory plasma.

The subject of this study was a mid-term evaluation of cardiovascular, respiratory and total non-accidental mortalities attributed to exposure to PM10, O3, NO2 and SO2 in the cities of Belgrade, Novi Sad and Nis, representing about 25% of the population of Serbia. The analysis was performed using AirQ+ modelling, by linking annual baseline mortality rates and daily pollutant exposure levels in 2011–2015 based on the cause-specific concentration–response functions. Estimated shares of annual mortality attributed to these pollutants, thanks to harmonizing of assessment methodologies, may stand next to and be compared with results obtained in previously conducted studies. The obtained premature deaths estimated within 95% confidence interval (in parentheses) and attributed to PM10, O3, NO2 and SO2 exposure were 2013 (1344–2677), 1411 (685–2086), 831 (555–1107) and 443 (333–530), respectively. Total non-accidental mortalities due to O3 and NO2 exposure were in the range of findings for other regions, while mortalities attributed to PM10 were higher. It was also found that cardiovascular mortality caused by these four pollutants was higher than respiratory mortality. Based on our results, efficient implementation of abatement strategies that would reduce PM10, O3 and SO2 concentrations to daily air quality limit values set by the World Health Organization could respectively prevent, in the three cities together, about 233 (156–310), 40 (19–59) and 71 (53–85) premature deaths per year.

Non-LTE modelling requires accurate atomic data e.g. collisional excitation and ionization cross-sections and rate coefficients. In order to improve the modeling of the solar photosphere, as well as to model atmospheres of other similar and cooler stars where the main constituent is also hydrogen, it is necessary to take into account the influence of all the relevant collisional processes on the excited-atom populations in weakly ionized hydrogen plasmas. In this context we present the data needed for the inclusion of the specific atomic collisional processes in the investigation of the optical and kinetic properties of weakly ionized stellar atmospheres layers. The ionization processes in collisions of excited hydrogen atoms with atoms in ground states were considered for the principal quantum numbers 2 ≤ n ≤ 20 and temperatures 4000 K ≤ T ≤ 20000 K.

In this paper, we investigate the chemi-ionization (CI) processes in atom-Rydberg atom collisions. The rate coefficients for CI processes in Li*(n) + Na, Li *(n) + Li, Na *(n) + Na and H *(n) + Li collisions are calculated for a wide range of temperatures (i.e. T <= 4000 K) and for the principal quantum numbers, 4 <= n <= 25. These processes are investigated with particular emphasis on the possibility of involving alkali metals as factors that might influence the optical properties and modelling of weakly ionized layers of different stellar atmospheres. The obtained rate coefficients are applied to models of the atmosphere of Io. Moreover, we present the further development of an investigation of CI processes for other possible applications in spectroscopy, such as in low-temperature laboratory plasma created in gas discharges (e.g. in microwave-induced discharges at atmospheric pressure), where such plasma conditions might be favourable.

In this work, we present a study dedicated to determination of the inverse bremsstrahlung absorption coefficients and the corresponding Gaunt factor of dense hydrogen-like stellar-atmosphere plasmas where electron density and temperature change in a wide range. A method suitable for this wide range is suggested and applied to the inner layers of the solar atmosphere, as well as the plasmas of partially ionized layers of some other stellar atmospheres (for example, some DA and DB white dwarfs) where the electron densities vary from 10(14) cm(-3) to 10(20) cm(-3) and temperatures from 6000 K to 300 000 K in the wavelength region of 10 nm <= lambda <= 3000 nm. The results of the calculations are illustrated by the corresponding figures and tables.

The possibility that the chemi-ionization processes in atom-Rydberg atom collisions, as well as the corresponding chemi-recombination processes, may be useful for the diagnostics, modelling, and confirmation of existence or non-existence of very dense weakly ionized domains in clouds in broad-line region of active galactic nuclei, has been considered. The obtained results demonstrate the fact that the considered chemi-ionization/recombination processes, which influence on the ionization level and atom excited-state populations, must have a very significant influence on the optical properties of the weakly ionized regions where the neutral hydrogen densities are larger than 10(12) cm(-3) since in such conditions they dominate over the relevant concurrent electron-atom collision processes. This can be used as a diagnostic method to find out if the domains with such densities exist or not. Additionally, our previous results obtained for principal quantum number 2 <= n <= 8 and 4000 K <= T <= 10 000 K are extended for principal quantum number 9 <= n <= 20 and 10 000 K <= T <= 20 000 K and also for low-temperature region (T < 4000 K) for 2 <= n <= 20.

Within the problem of the finding of the mean potential energy of the charged particle in the plasma in this work a classification of physical systems (electrolytes, dusty plasmas, plasmas) is made based on consideration, or lack thereof, of a few special additional conditions. The system considered here, as well as other systems which are described with those additional conditions imposed are treated as the systems of the "closed" type, while the systems where those conditions are fully neglected - as being of the "open" type. In the our previous investigation one- and two component systems were examined. Here, as the object of investigation fully ionized electron-ion plasma with positive charged ions of two different kinds, including the plasmas of higher non-ideality, is chosen for the first time. For such plasma a new self-consistent model method of describing electrostatic screening is developed which includes all the necessary additional conditions. By this method such extremely significant phenomena as electron-ion and ion-ion correlations are included in the used model. The characteristics of the considered plasmas in a wide region of electron densities and temperatures are calculated. All the obtained results, including a comparison with systems of the "open" type are specifically discussed.

Here, we will consider the influence of the (n-n')-mixing processes during atom Rydberg-atom collision processes on the intensity of chemi-ionization process. We will take into account H(1s) + H*(n) and He(1s(2)) + He*(n,l) collisional systems, where the principal quantum number n >> 1. The corresponding calculations of the chemi-ionization rate coefficients are performed for the temperature region characteristic for the solar and DB white dwarf atmosphere.

In this paper, the rate coefficients of the chemi-ionization processes in H(1s) + H*(n, l) and He(1s(2)) + He*(n, l) collisions (where the principal quantum number n a parts per thousand << 1) are determined for the first time, taking into account the influence of the corresponding (n - n('))-mixing processes. It is demonstrated that the inclusion of (n - n(')) mixing in the calculation influences the values of chemi-ionization rate coefficients significantly, particularly in the lower part of the block of Rydberg states. The interpretation of this influence is based on two existing methods of describing inelastic processes in symmetrical atom-Rydberg-atom collisions. The calculations of the chemi-ionization rate coefficients are performed for the temperature region that is characteristic of solar and DB white-dwarf atmospheres.

The values of electrical conductivity of plasma of stars with a magnetic field or moving in the magnetic field of the other component in a binary system could be of significant interest, since they are useful for the study of thermal evolution of such objects, cooling, nuclear burning of accreted matter, and the investigation of their magnetic fields. So, on the basis of numerically calculated values for the dense plasma conductivity in an external HF electric field, we determine the HF characteristics of astrophysical plasmas under extreme conditions. The examined range of frequencies covers the IR, visible and near UV regions and consider electronic number density and temperature are in the ranges of $10^{21} \textrm{cm}^{-3} \le Ne$ and 20 000 $\le T$, respectively. The method developed here represents a powerful tool for research into white dwarfs with different atmospheric compositions (DA, DC etc.), and for investigation of some other stars (M-type red dwarfs, Sun etc.).