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

Abstract

In our previous research, it has been demonstrated that such inelastic processes in atom Rydbergatom collisions, 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 will be discussed. 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 n >> 1. It will be demonstrated that the inclusion of (nn') 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 of the inelastic processes in symmetrical atom Rydberg-atom collisions.

Chemi-ionization processes in Narrow-Line Seyfert 1 Galaxies

“…It is pointed out that the Rydberg states that arise have large dipole moments, leading to strong absorption in the infrared, and also to the appearance of polarization [7]. It should also be noted that the processes (1.1) and (1.2) are very important for modelling the moderately ionized layers of solar photosphere which is shown by the results obtained in [8,9,10].…”

Symmetric Atom–Atom and Ion–Atom Processes in Stellar Atmospheres

“…From the results [37,38], it follows that processes (1) are significant for such hydrogen and helium plasmas with the ratio Ne/Na < 10 −3 , where Ne and Na are the free electron and ground state atom density. Accordingly, these processes are significant for the stellar atmospheres that contain the corresponding weakly ionized layers.…”

Atom-Rydberg atom chemi-ionization/recombination processes in the hydrogen clouds in Broad Line Region of AGNs

“…These results, as well as the papers Mihajlov & Dimitrijević (1986, 1992 etc., with the analysis of radiation ion-atom processes, suggested that the chemi-ionization processes (3) and ( 4) and the chemi-recombination processes ( 5) and ( 6) may have a significant influence on excited-atom populations in the weakly ionized plasma of stellar atmospheres. The importance of the hydrogen case for the corresponding layers in solar photosphere is examined and demonstrated in Mihajlov et al (1997aMihajlov et al ( , 2011Mihajlov et al ( , 2016, and for the helium case in the atmospheres of DB white dwarfs with T eff = 12000−18000K) in Mihajlov et al (2003aMihajlov et al ( , 2015Mihajlov et al ( , 2016. We note as well that in Mihajlov et al (2003bMihajlov et al ( , 2007, the chemiionization processes with A = H(1s) have been included ab initio in the PHOENIX code (see Baron & Hauschildt 1998), in order to investigate their influence on the excited H atom populations, the electron density, and the profiles of H lines in the atmosphere of an M red dwarf with the effective temperature T eff = 3800 K. It has been shown that these processes with n ≤ 8 have a strong influence on the population of excited states in H atom as well as to the electron density.…”