arXiv subjects

Rustam V. Koneev

Publications and source records attributed to Rustam V. Koneev.

6 recordsLinked to original sources

arXiv2026

Non-dipole effects in two-photon double ionization of the K-shell of a beryllium-like atomic ion

In the second order of the non-relativistic quantum perturbation theory and outside the framework of the dipole approximation for the operator of the radiation transition between continuum-spectrum states, the analytical structures and absolute values of the generalized cross-sections of the two-photon double ionization of the K-shell of beryllium-like ions of titanium (Ti18+), iron (Fe22+) and zinc (Zn26+) atoms were predicted. It has been established that taking into account non-dipole effects by several orders of magnitude (giant non-dipole effect) reduces the generalized cross-sections calculated within the framework of the dipole approximation. It has also been established that at high (12.5 - 28 keV) energies of the absorbed photons, the generalized cross-section of the two-photon double ionization of the K-shell is several orders of magnitude greater than the generalized cross-section of the single ionization. At the same time, as was to be expected, the transition from a neon-like ion to a beryllium-like ion is accompanied by a significant increase in the role of non-dipole effects.

physics.atom-ph↗

arXiv2025

Two-photon ionization of the K-shell of ions of the isonuclear sequence of a heavy atom

The shape and absolute values of the generalized cross-sections of the two-photon resonant single ionization of the K-shell of ions of the isonuclear sequence of a heavy nickel atom (28Ni - Ni26+ - Ni24+ - Ni18+) have been theoretically predicted. The complete wave functions of ionization states have been obtained in the single-configuration Hartree-Fock approximation. The effects of the occurrence of giant resonances in the subthreshold region of the generalized ionization cross-section and destructive quantum interference of the amplitudes of the probability of radiation transitions have been established. The leading role of the d-symmetry of the final state of ionization in determining the total generalized crosssection in the energy region of absorbed photons in the hard X-ray range has also been established.

physics.atom-ph↗

arXiv2025

On the Extended Hilbert Space in the theory of the multielectron atom

The construction of the Extended Hilbert Space (EHS) is presented in the form of a direct sum of the spaces of vectors of finite and infinite norms as the main space in the mathematical formalism of quantum mechanics of a multielectron atom. On the example of constructing the analytical structure of the probability amplitude 1s - 3p of photoexcitation of a neon atom, the implementation of the EHS - construct for solving the equations of the self-consistent Hartree-Fock field is given.

physics.atom-ph↗

arXiv2025

On summation of $3j$-Wigner symbols

Within the framework of the theory of irreducible tensor operators, using well-known general analytical results for double sums ($\sum_{jm}$) of products of two $3j$-Wigner symbols, analytical expressions for single sums ($\sum_m$) for the values $j_1 = j_2 = 1$ and $j = 2$ parameters of the upper row $3j$-Wigner symbol are specified. The expressions obtained supplement the well-known analytical results of the theory of angular momentum and are in demand in solving, in particular, such problems of atomic physics as the construction of a nonrelativistic quantum theory of single and double bremsstrahlung when a photon is scattered by an atom (atomic ion) (Hopersky et al [6,7,8]) and two-photon resonance single ionization of the deep shell of an atomic ion (Hopersky et al [9]).

physics.atom-ph↗

arXiv2025

On the dipole approximation in the theory of photoionization of the atom

In the nonrelativistic many-electron approximation of the theory of photoionization of the atom in the formalism of secondary quantization and the theory of irreducible tensor operators, analytical structures for the quadrupole transition operator and its matrix element are specified. A new form of the nonrelativistic criterion for the applicability of the dipole approximation is formulated as the ratio of the complete cross sections of one-electron photoionization of an atom via the channels of dipole and quadrupole transitions.

physics.atom-ph↗

arXiv2025

Two-photon resonance single ionization of the K-shell of an atomic ion

The analytical structure and absolute values of the generalized cross-section of the two-photon resonance single ionization of the K-shell of a heavy neon-like ion of an iron atom (Fe$^{16+}$) were theoretically predicted. A pronounced resonant subthreshold structure of the generalized cross-section and the effect of destructive quantum interference of the probability amplitudes of radiation transitions into virtual excited states of p-symmetry have been established. The presence of a valence 2p$^6$-shell in the ion backbone causes the production of an additional giant resonance of the generalized cross-section as the effect of the "reverse" hard X-ray emission of K$\alpha$-type 1s$^2$(2s$^2$)2p$^5$ + $\hbar\omega \to$ 1s(2s$^2$)2p$^6$. A scheme of the proposed experiment with linearly polarized X-ray photons is presented to verify the theoretical results obtained.

physics.optics↗