arXiv subjects
Publications and source records attributed to I. A. Mikhailov.
We show that the high energy limit for the amplitude of the double electron capture to the bound state of the Coulomb field of a nucleus with emission of a single photon is determined by behavior of the wave function in the vicinity of the singular triple coalescence point.
Recombination of H3+ with electrons was studied in a low temperature plasma in helium. The plasma recombination rate is driven by two body, H3+ + e, and three-body, H3+ + e + He, processes with the rate coefficients 7.5x10^{-8}cm3/s and 2.8x10^{-25}cm6/s correspondingly at 260K. The two-body rate coefficient is in excellent agreement with results from storage ring experiments and theoretical calculations. We suggest that the three-body recombination involves formation of highly excited Rydberg neutral H3 followed by an l- or m- changing collision with He. Plasma electron spectroscopy indicates the presence of H3.
We calculate the electron energy spectrum of ionization by a high energy photon, accompanied by creation of electron-positron pair. The total cross section of the process is also obtained. The asymptotics of the cross section does not depend on the photon energies. At the photon energies exceeding a certain value $ω_0$ this appeares to to be the dominant mechanism of formation of the ions. The dependence of $ω_0$ on the value of nuclear charge is obtained. Our results are consistent with experimental data.
The total cross section for double ionization of lithiumlike ions by a high-energy photon is calculated in leading order of the nonrelativistic perturbation theory. The partial contributions due to simultaneous and sequential emissions of two electrons are taken into account. The cross section under consideration is shown to be related to those for double photoeffect on the ground and excited 2^{1,3}S states of heliumlike ions. The double-to-single ionization ratio is equal to R = 0.288/Z^2 for lithiumlike ions with moderate nuclear charge numbers Z. However, even for the lightest three-electron targets such as Li and Be^+, analytical predictions are found to be in good agreement with the numerical calculations performed within the framework of different rather involved approaches.