K. Koshelev | Saint-Petersburg State University of Industrial Technologies and Design (original) (raw)

Papers by K. Koshelev

One more mode developed to get eigen energies and states for the one-electron Dirac's equation wi... more One more mode developed to get eigen energies and states for the one-electron Dirac's equation with spherically symmetric bound potential. For the particular case of the Coulomb potential it was shown that the method is free of so called spurious states. The procedure could be adapted to receive highly exited states with great precision.

Different q-factor definitions are considered. The formula connecting different q-factors is give... more Different q-factor definitions are considered. The formula connecting different q-factors is given. Also it is pointed the way to find all the q-factors from experimental data.

One more mode developed to get eigen energies and states for the one-electron Dirac's equation wi... more One more mode developed to get eigen energies and states for the one-electron Dirac's equation with spherically symmetric bound potential. For the particular case of the Coulomb potential it was shown that the method is free of so called spurious states. The procedure could be adapted to receive highly exited states with great precision.

Different q-factor definitions are considered. The formula connecting different q-factors is give... more Different q-factor definitions are considered. The formula connecting different q-factors is given. Also it is pointed the way to find all the q-factors from experimental data.

Japanese Journal of Applied Physics, 2012

Abstract ZEP brand electron beam resists are well-known for their high sensitivity and etch durab... more Abstract ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. The various performance metrics such as sensitivity, contrast, and resolution of ZEP resist depend strongly on the development process. In this work, we investigate the ...

Physics Letters A, 2004

We discuss the possibility of new determination of the quadrupole moment of 209 83 Bi nucleus fro... more We discuss the possibility of new determination of the quadrupole moment of 209 83 Bi nucleus from the hyperfine structure (HFS) of the highly charged (HCI) 209 83 Bi ions. The results of the accurate numerical evaluation of the HFS in 209 83 Bi HCI are presented. The evaluation of the HFS of the few-electron Bi ions and comparison of the results with the experimental data (not yet existing) would provide a new, totally independent determination of the electric quadrupole moment for Bi nucleus Q( 209 83 Bi). An accurate determination of Q( 209 83 Bi) from the HFS calculations for neutral 209 83 Bi of −0.516(15) (10 −28 m 2 ) [1] has been published and adopted as the new, '2001' standard value [2,3]. It should be confirmed. The previous values ranged from −0.370(26) to −0.77(1) (10 −28 m 2 ), see Refs. [1,4]. Of them, the pionic value of −0.500(80) (10 −28 m 2 ) was selected for the previous, '1992' set of moments.

Physical Review A, 2003

ABSTRACT

Optics and Spectroscopy, 2003

Physical Review A, 2009

In this paper we calculated the relativistic corrections to transition frequencies ͑q factors͒ of... more In this paper we calculated the relativistic corrections to transition frequencies ͑q factors͒ of Fe I for the transitions from the even-and odd-parity states to the ground state. We also carried out isotope-shift calculations in Fe I and Fe II.

The lowest-order interelectron interaction and electron self-energy radiative corrections to the ... more The lowest-order interelectron interaction and electron self-energy radiative corrections to the hyperfine
structure intervals for the 2p3/2 state of Li-like, B-like, and N-like 83
209Bi ions are calculated. The contributions
of the magnetic dipole, electric quadrupole, and magnetic octupole moments are included. The ‘‘dynamical’’
model of the hyperfine interaction is employed, where the electron is assumed to interact with the valence
proton in 83
209Bi nucleus via the exchange of a virtual photon. Within this model the magnetic and the electric
moment distributions inside the nucleus are simultaneously taken into account.

Two forms of relativistic density functional are derived from Dirac equation. Based on their stru... more Two forms of relativistic density functional are derived from Dirac equation. Based on their structure analysis model of split electron is proposed. In this model electric charge and mass of electron behave like two point-like particles. It is shown that two electrons obeying this model cannot occupy the same quantum state. Empirical verification of the model is discussed.

Japanese Journal of Applied Physics, Jun 20, 2012

ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. Th... more ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. The various performance metrics such as sensitivity, contrast, and resolution of ZEP resist depend strongly on the development process. In this work, we investigate the development of ZEP-520 resist through contrast curves, dense gratings, and surface roughness measurements using three different classes of developer systems of varying solvation strength, ZED-N50, methyl isobutyl ketone (MIBK) : isopropyl alcohol (IPA) 1:3, and IPA : H2O 7:3, at the ambient temperature (22 °C) and cold (-15 °C) development conditions. In order to provide a deeper insight into the ZEP development process, we propose a novel kinetic model of dissolution for ZEP, and develop an efficient analytical method that allows determining the microscopic parameters of ZEP dissolution based on experimental contrast curves. We also observe experimentally and characterize the negative tone behavior of ZEP for dense grating patterning and compare its performance with positive tone behavior.

Journal of Vacuum Science & Technology B, Sep 22, 2011

A modern alternative to the positive-tone PMMA resist is the ZEP 520A (Nippon Zeon) brand co-poly... more A modern alternative to the positive-tone PMMA resist is the ZEP 520A (Nippon Zeon) brand co-polymer resist, which offers a higher sensitivity and etch durability for electron beam lithography. However, the molecular mechanisms are not entirely understood, and the relative performance of two resists for various process conditions of nanofabrication is not readily predictable. The authors report a thorough experimental comparison of the performance of PMMA 950k and ZEP 520A resists in MIBK:IPA, ZED, and IPA:water developers. Interestingly, ZEP resist performance was found to depend significantly on the developer. ZED developer increases the sensitivity, whereas IPA:water optimizes line edge roughness and conceivably the resolution at the expense of sensitivity. The authors also describe two alternative numerical models, one assuming an enhancement of the main chain scission in ZEP as a result of electronic excitations in side groups, and another without such enhancement. In the second case, the differences in ZEP and PMMA resists performance are attributed to their different interaction with the developers. Using both approaches, the authors parameterize the respective models of ZEP development by fitting numerical results to the experimental resist morphologies, and analyze the outcomes.

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2010

The authors report a numeric simulation tool that they developed for the modeling and analysis of... more The authors report a numeric simulation tool that they developed for the modeling and analysis of electron beam lithography ͑EBL͒ of nanostructures employing a popular positive tone resist polymethylmethacrylate ͑PMMA͒. Modeling and process design for EBL fabrication of 5-50 nm PMMA structures on solid substrates is the target purpose of the simulator. The simulator is functional for exposure energies from 1 to 50 keV with arbitrary writing geometries. The authors employ a suite of kinetic models for the traveling of primary, secondary, and backscattered electrons in the resist, compute three-dimensional ͑3D͒ distributions of the yield of main-chain scission in PMMA, and convert these into the local volume fractions of fragments of various sizes. The kinetic process of development is described by the movement of the resist-developer interface with the rate derived from the mean-field theory of polymer diffusion. The EBL simulator allows the computation of detailed 3D distributions of the yield of main-chain scission in PMMA for various conditions of exposure, the corresponding volume fractions of small fragments, and the clearance profiles as functions of the development in time and temperature. This article describes the models employed to simulate the EBL exposure and development, reports examples of the computations, and presents comparisons of the predicted development profiles with experimental cross-sectional resist profiles in dense gratings.

Physical Review A, 2007

Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine-struc... more Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine-structure constant ␣. The resonance absorption lines of Fe II from objects at cosmological distances are used in a search for the possible variation of ␣ in the course of cosmic time. In this paper we calculated the dependence of the transition frequencies on ␣ 2 ͑q factors͒ for Fe II ion. We found corrections to these coefficients from valencevalence and core-valence correlations and from the Breit interaction. Both the core-valence correlation and Breit corrections to the q factors appeared to be larger than had been anticipated previously. Nevertheless our calculation confirms that the Fe II absorption lines seen in quasar spectra have large q factors of both signs and thus the ion Fe II alone can be used in the search for the ␣ variation at different cosmological epochs.

Drafts by K. Koshelev

Strict density functional formula for one-electron Schrödinger equation with Coulomb potential is... more Strict density functional formula for one-electron Schrödinger equation with Coulomb potential is deduced as non-relativistic limit of relativistic density functional received earlier. The functional of energy coincides, up to the factor, with well known classic formula for the energy of electric charge distribution in electrostatic field. It is shown that the formula is valid as for ground as for any excited bound state of electron. Finally it is pointed out a group of potentials apart from pure Coulomb one that achieved result stands for.

Article introduces a concept of hidden time and gives interpretation of wave function as its meas... more Article introduces a concept of hidden time and gives interpretation of wave function as its measure. Standard probabilistic approach to explain the meaning of wave function is shown to be the natural consequence of proposed interpretation as well as the superposition principle.

One more mode developed to get eigen energies and states for the one-electron Dirac's equation wi... more One more mode developed to get eigen energies and states for the one-electron Dirac's equation with spherically symmetric bound potential. For the particular case of the Coulomb potential it was shown that the method is free of so called spurious states. The procedure could be adapted to receive highly exited states with great precision.

Different q-factor definitions are considered. The formula connecting different q-factors is give... more Different q-factor definitions are considered. The formula connecting different q-factors is given. Also it is pointed the way to find all the q-factors from experimental data.

One more mode developed to get eigen energies and states for the one-electron Dirac's equation wi... more One more mode developed to get eigen energies and states for the one-electron Dirac's equation with spherically symmetric bound potential. For the particular case of the Coulomb potential it was shown that the method is free of so called spurious states. The procedure could be adapted to receive highly exited states with great precision.

Different q-factor definitions are considered. The formula connecting different q-factors is give... more Different q-factor definitions are considered. The formula connecting different q-factors is given. Also it is pointed the way to find all the q-factors from experimental data.

Japanese Journal of Applied Physics, 2012

Abstract ZEP brand electron beam resists are well-known for their high sensitivity and etch durab... more Abstract ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. The various performance metrics such as sensitivity, contrast, and resolution of ZEP resist depend strongly on the development process. In this work, we investigate the ...

Physics Letters A, 2004

We discuss the possibility of new determination of the quadrupole moment of 209 83 Bi nucleus fro... more We discuss the possibility of new determination of the quadrupole moment of 209 83 Bi nucleus from the hyperfine structure (HFS) of the highly charged (HCI) 209 83 Bi ions. The results of the accurate numerical evaluation of the HFS in 209 83 Bi HCI are presented. The evaluation of the HFS of the few-electron Bi ions and comparison of the results with the experimental data (not yet existing) would provide a new, totally independent determination of the electric quadrupole moment for Bi nucleus Q( 209 83 Bi). An accurate determination of Q( 209 83 Bi) from the HFS calculations for neutral 209 83 Bi of −0.516(15) (10 −28 m 2 ) [1] has been published and adopted as the new, '2001' standard value [2,3]. It should be confirmed. The previous values ranged from −0.370(26) to −0.77(1) (10 −28 m 2 ), see Refs. [1,4]. Of them, the pionic value of −0.500(80) (10 −28 m 2 ) was selected for the previous, '1992' set of moments.

Physical Review A, 2003

ABSTRACT

Optics and Spectroscopy, 2003

Physical Review A, 2009

In this paper we calculated the relativistic corrections to transition frequencies ͑q factors͒ of... more In this paper we calculated the relativistic corrections to transition frequencies ͑q factors͒ of Fe I for the transitions from the even-and odd-parity states to the ground state. We also carried out isotope-shift calculations in Fe I and Fe II.

The lowest-order interelectron interaction and electron self-energy radiative corrections to the ... more The lowest-order interelectron interaction and electron self-energy radiative corrections to the hyperfine
structure intervals for the 2p3/2 state of Li-like, B-like, and N-like 83
209Bi ions are calculated. The contributions
of the magnetic dipole, electric quadrupole, and magnetic octupole moments are included. The ‘‘dynamical’’
model of the hyperfine interaction is employed, where the electron is assumed to interact with the valence
proton in 83
209Bi nucleus via the exchange of a virtual photon. Within this model the magnetic and the electric
moment distributions inside the nucleus are simultaneously taken into account.

Two forms of relativistic density functional are derived from Dirac equation. Based on their stru... more Two forms of relativistic density functional are derived from Dirac equation. Based on their structure analysis model of split electron is proposed. In this model electric charge and mass of electron behave like two point-like particles. It is shown that two electrons obeying this model cannot occupy the same quantum state. Empirical verification of the model is discussed.

Japanese Journal of Applied Physics, Jun 20, 2012

ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. Th... more ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. The various performance metrics such as sensitivity, contrast, and resolution of ZEP resist depend strongly on the development process. In this work, we investigate the development of ZEP-520 resist through contrast curves, dense gratings, and surface roughness measurements using three different classes of developer systems of varying solvation strength, ZED-N50, methyl isobutyl ketone (MIBK) : isopropyl alcohol (IPA) 1:3, and IPA : H2O 7:3, at the ambient temperature (22 °C) and cold (-15 °C) development conditions. In order to provide a deeper insight into the ZEP development process, we propose a novel kinetic model of dissolution for ZEP, and develop an efficient analytical method that allows determining the microscopic parameters of ZEP dissolution based on experimental contrast curves. We also observe experimentally and characterize the negative tone behavior of ZEP for dense grating patterning and compare its performance with positive tone behavior.

Journal of Vacuum Science & Technology B, Sep 22, 2011

A modern alternative to the positive-tone PMMA resist is the ZEP 520A (Nippon Zeon) brand co-poly... more A modern alternative to the positive-tone PMMA resist is the ZEP 520A (Nippon Zeon) brand co-polymer resist, which offers a higher sensitivity and etch durability for electron beam lithography. However, the molecular mechanisms are not entirely understood, and the relative performance of two resists for various process conditions of nanofabrication is not readily predictable. The authors report a thorough experimental comparison of the performance of PMMA 950k and ZEP 520A resists in MIBK:IPA, ZED, and IPA:water developers. Interestingly, ZEP resist performance was found to depend significantly on the developer. ZED developer increases the sensitivity, whereas IPA:water optimizes line edge roughness and conceivably the resolution at the expense of sensitivity. The authors also describe two alternative numerical models, one assuming an enhancement of the main chain scission in ZEP as a result of electronic excitations in side groups, and another without such enhancement. In the second case, the differences in ZEP and PMMA resists performance are attributed to their different interaction with the developers. Using both approaches, the authors parameterize the respective models of ZEP development by fitting numerical results to the experimental resist morphologies, and analyze the outcomes.

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2010

The authors report a numeric simulation tool that they developed for the modeling and analysis of... more The authors report a numeric simulation tool that they developed for the modeling and analysis of electron beam lithography ͑EBL͒ of nanostructures employing a popular positive tone resist polymethylmethacrylate ͑PMMA͒. Modeling and process design for EBL fabrication of 5-50 nm PMMA structures on solid substrates is the target purpose of the simulator. The simulator is functional for exposure energies from 1 to 50 keV with arbitrary writing geometries. The authors employ a suite of kinetic models for the traveling of primary, secondary, and backscattered electrons in the resist, compute three-dimensional ͑3D͒ distributions of the yield of main-chain scission in PMMA, and convert these into the local volume fractions of fragments of various sizes. The kinetic process of development is described by the movement of the resist-developer interface with the rate derived from the mean-field theory of polymer diffusion. The EBL simulator allows the computation of detailed 3D distributions of the yield of main-chain scission in PMMA for various conditions of exposure, the corresponding volume fractions of small fragments, and the clearance profiles as functions of the development in time and temperature. This article describes the models employed to simulate the EBL exposure and development, reports examples of the computations, and presents comparisons of the predicted development profiles with experimental cross-sectional resist profiles in dense gratings.

Physical Review A, 2007

Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine-struc... more Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine-structure constant ␣. The resonance absorption lines of Fe II from objects at cosmological distances are used in a search for the possible variation of ␣ in the course of cosmic time. In this paper we calculated the dependence of the transition frequencies on ␣ 2 ͑q factors͒ for Fe II ion. We found corrections to these coefficients from valencevalence and core-valence correlations and from the Breit interaction. Both the core-valence correlation and Breit corrections to the q factors appeared to be larger than had been anticipated previously. Nevertheless our calculation confirms that the Fe II absorption lines seen in quasar spectra have large q factors of both signs and thus the ion Fe II alone can be used in the search for the ␣ variation at different cosmological epochs.

Strict density functional formula for one-electron Schrödinger equation with Coulomb potential is... more Strict density functional formula for one-electron Schrödinger equation with Coulomb potential is deduced as non-relativistic limit of relativistic density functional received earlier. The functional of energy coincides, up to the factor, with well known classic formula for the energy of electric charge distribution in electrostatic field. It is shown that the formula is valid as for ground as for any excited bound state of electron. Finally it is pointed out a group of potentials apart from pure Coulomb one that achieved result stands for.

Article introduces a concept of hidden time and gives interpretation of wave function as its meas... more Article introduces a concept of hidden time and gives interpretation of wave function as its measure. Standard probabilistic approach to explain the meaning of wave function is shown to be the natural consequence of proposed interpretation as well as the superposition principle.

Rigorous density functional form is derived ab initio for relativistic electron obeying Dirac equ... more Rigorous density functional form is derived ab initio for relativistic electron obeying Dirac equation. Lagrange equation is received and it is demonstrated that density function for any bound state of electron is an extremal for that functional.

Proceedings of Regional Informatics 2024, 2024

Author of the article offers a methodology for quantum computer software automatic generation. To... more Author of the article offers a methodology for quantum computer software automatic generation. To this goal, the fact of equivalence of the algorithm and unitary operator is employed. Then concept of natural code for quantum information is introduced. After it is demonstrated that for a particular quantum algorithm written in this coding not less efficient conventional or classic algorithm exists.

The paper describes traffic observation at the airfield for the aircraft collision prevention sys... more The paper describes traffic observation at the
airfield for the aircraft collision prevention system. Application
of neural network is shown to be effective for aircraft collision
prevention during taking off, landing, and moving on the
runway and taxiway.