I. Yu. Kretinin

Dynamic polarizabilities of atoms in their low-excited states : He, Be, Mg and Ca

The quantum defect Green function formalism is applied to calculate the dynamic scalar and tensor polarizabilities of some atoms in their excited states (21S, 23S, 21P and 23P for He, 21P and 23P for Be, 33P for Mg and 43P for Ca). Experimental and calculated oscillator strength values were used to provide an account for low-excited states (reduce–adding correction of the Green function) while the high-excited and continuum states are accounted semi-analytically. The calculated polarizability values are in good (within several per cent) agreement with the available experimental data and the ab initio numerical data.

Correction to the tunneling theory in atoms

The theory of the tunneling ionization of atoms with several outer-shell electrons is specified. Numerical calculations for the noble-gas atoms are performed.

Born–Hartree–Bethe approximation in the theory of inelastic electron–molecule scattering

We propose a new approximation in the theory of inelastic electron–atom and electron–molecule scattering. Taking into account the completeness property of atomic and molecular wavefunctions, considered in the Hartree approximation, and using Bethes parametrization for electronic excitations during inelastic collisions via the mean excitation energy, we show that the calculation of the inelastic total integral cross-sections (TICS), in the framework of the first Born approximation, involves only the ground-state wavefunction. The final analytical formula obtained for the TICS, i.e. for the sum of elastic and inelastic ones, contains no adjusting parameters. Calculated TICS for electron scattering by light atoms and molecules (He, Ne, and H2) are in good agreement within the experimental data; results show asymptotic coincidence for heavier ones (Ar, Kr, Xe and N2).

Polarizability of the fine-structure components of low excited states of-the F, Cl, and Br atoms

The dynamic scalar, tensor, and pseudovector polarizabilities of the low excited states (ns)4PJ of the F, Cl, and Br atoms (n = 3, 4, and 5, respectively) are calculated for all the levels of the fine-structure multiplets with J = 5/2, 3/2, and 1/2 with the use of the quantum detect Green’s function, proposed earlier.

Method of the quantum defect Green's function for calculation of dynamic atomic polarizabilities

The quantum defect Green’s function enabling one to take into account exactly the contribution of highly excited and continuum states to the polarizability is found. The contribution of the ground and low-lying excited states is taken into account by using experimental values of the corresponding oscillator strengths. The good accuracy of the method proposed is demonstrated by calculation of the scalar dipole dynamic polarizabilities of noble gas atoms with consideration of the fine structure of the terms.

Polarization bremsstrahlung in α decay

A mechanism of formation of electromagnetic radiation that accompanies α decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of α particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in α decay.

An aerodynamic model of the collisional alignment of the cations of macromolecules

The collisional alignment of macromolecule ions in an external electric field was studied based on the scaling of the dimensions and properties of a real macromolecule and its environment into the domain of classical mechanics. The calculations were carried out within the framework of computational fluid dynamics for a streamlined prolate spheroid macromolecule; they showed that the collisional alignment of ions occurred in an oscillatory mode with a characteristic time of several nanoseconds.

Charge transfer processes in collisions of slow highly charged ions with polar molecules CO and C3H8

Charge transfer processes resulting from low energy collisions of polar molecules CO and C3H8 with highly charged Be2+ and B2+ ions have been investigated experimentally and theoretically. The potential for the one–electron exchange interaction between a polar molecule and highly charged atomic ion were obtained in closed analytical form in the framework of a semiclassical approach. Obtained results were used for close–coupling calculations of total cross sections for single electron transfer in the studied reactions.

Molecular polarizability in quantum defect theory: Non-polar molecules

The Green function in the quantum defect theory provides an exact account for the high-excited and continuum electronic states. We modify it by taking into account the ground and low-excited states using their wavefunctions calculated ab initio. As an application we present simple and efficient semi-analytical method for calculation of dynamic polarizabilities of nonpolar molecules. The method is applied to alkali dimers Li

Method of the reduced-added Green function in the calculation of atomic polarizabilities

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