Персона: Ткаля, Евгений Викторович
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Институт лазерных и плазменных технологий
Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.
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Ткаля
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Евгений Викторович
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- ПубликацияТолько метаданныеCharge Properties of Thorium Implanted in Silicon Oxide(2020) Kurelchuk, U. N.; Borisyuk, P. B.; Nikolaev, A. V.; Tkalya, E. V.; Курельчук, Ульяна Николаевна; Борисюк, Петр Викторович; Николаев, Александр Васильевич; Ткаля, Евгений Викторович© 2020, Pleiades Publishing, Ltd.Abstract: A study of thorium atoms implanted in silicon oxide was carried out within the density functional theory method. The charge properties of Th in the ThO2:nSiO2 and Th:nSiO2 compounds, where Th acts as an interstitial and substitutional impurity in cristobalite, have been studied. Geometric optimization of structures is carried out with allowance for electron-electron interactions, self-consistent distribution of electron density is investigated, and Bader effective charges are estimated.
- ПубликацияТолько метаданныеAutoelectronic emission and charge relaxation of thorium ions implanted into a thin-film silicon oxide matrix(2021) Borisyuk, P. V.; Chubunova, E. V.; Kolachevsky, N. N.; Lebedinskii, Y. Y.; Tkalya, E. V.; Vasilyev, O. S.; Yakovlev, V. P.; Борисюк, Петр Викторович; Чубунова, Елена Витальевна; Лебединский, Юрий Юрьевич; Ткаля, Евгений Викторович; Васильев, Олег Станиславович; Яковлев, Валерий ПетровичAn ensemble of thorium-229 ions embedded by pulsed laser implantation into a matrix of a broadband dielectric-silicon oxide is studied. The results of the experimental investigation of thorium ions' lifetime as charged components of the Th+/SiO2/Si system formed immediately after laser implantation are presented. The modelled theoretical description takes into account the instantaneous charging of the surface via laser implantation followed by charge relaxation due to the effect of autoelectronic emission that leads to time dependent partial neutralization of the surface charge by tunneling electrons. It was found that the lifetime of Th+ ions on the SiO2 surface can exceed 10 s, which would be an attractive opportunity for studying the nuclear low-lying isomeric transition in the thorium-229 isotope.
- ПубликацияТолько метаданныеCross section of the Coulomb excitation of Th-229m by low energy muons(2021) Tkalya, E. V.; Ткаля, Евгений ВикторовичThe inelastic scattering cross section for muons, mu(-), with energies E = 9-100 eV from the Th-229 nuclei is calculated in the framework of the second order of the perturbation theory for quantum electrodynamics. The dominant contribution to the excitation of the low energy isomer Th-229m(3/2(+), 8.19 +/- 0.12 eV) originates from the E2 multipole. The excitation cross section reaches the value of 10(-12) cm(2) in the range E approximate to 10 eV. This value is four to five orders of magnitude larger than the electron excitation cross section and is sufficient for the efficient excitation of Th-229m on the muon beam at the next generation of muon colliders.
- ПубликацияТолько метаданныеDecay of the low-energy nuclear Th 229m isomer via atomic Rydberg states(2019) Tkalya, E. V.; Ткаля, Евгений Викторович© 2019 American Physical Society.In the paper, a unique process of the decay of the Th229m(3/2+,8.28±0.17 eV) low-energy nuclear isomer via the internal conversion (IC) channel on Rydberg states is considered for the first time. The Rydberg atom Th+229m+eRy- is a unique object where IC is possible exclusively on the Rydberg electron eRy-. It is shown that in the Th4+229m+eRy- system (a) IC on the electron states with relatively small values of the principal quantum number n and the orbital moment l is practically completely suppressed, (b) IC probability, WIC, on the ψns1/2(r) states is proportional to |ψns1/2(0)|2 and can be related with the energy of the hyperfine interaction of the Rydberg electron with the nucleus, (c) WIC decreases rapidly with the increase of n in the range from 10 to 50, and in the range n 150WIC changes as const/n3 typical for hydrogen-like ions, and (d) at n≈10-30, WIC as a function of l has a characteristic "knee" between l=3 and l=4, i.e., a decrease of three orders of magnitude in WIC due to the qualitative change in the ratio between the centrifugal and shielding potentials.
- ПубликацияТолько метаданныеExcitation of the low-energy Th-229m isomer Th in the electron bridge process via the continuum(2019) Taichenachev, A. V.; Tolstikhina, I. Yu.; Yudin, V. I.; Borisyuk, P. V.; Kolachevsky, N. N.; Tkalya, E. V.; Борисюк, Петр Викторович; Ткаля, Евгений ВикторовичThe paper studies the excitation of the Th-229 nucleus to the anomalously low-lying isomeric state 3/2(+)(8.28 +/- 0.17 eV) in the electron bridge process via the continuum of the electron spectrum. Resonant excitation of the nucleus was found to be always possible in the scheme, no matter where the electron levels of an atom or ion were located. Formulas for the excitation cross section by narrow and wide laser lines are obtained. In the resonance, where the process under consideration turns into laser photoionization followed by nuclear excitation in electron capture, the cross section of the process was shown to be comparable in magnitude with that of the photoionization of the thorium atom. Experimental schemes for testing the effect were proposed, which would allow measuring the frequency of the nuclear isomeric transition 3/2(+) -> 5/2(+) to a high precision, which is the first-priority (and still unresolved) task for creating a nuclear clock.
- ПубликацияОткрытый доступСпектроскопическое исследование кристаллических пленок неона, выращенных на золотой подложке(2023) Курельчук, У. Н.; Борисюк, П. В.; Чубунова, Е. В.; Домашенко, М. С.; Каражанов, С. Ж.; Колачевский, Н. Н.; Лебединский, Ю. Ю.; Мызин, Д. А.; Николаев, А. В.; Ткаля, Е. В.; Ткаля, Евгений Викторович; Мызин, Дмитрий Анатольевич; Чубунова, Елена Витальевна; Борисюк, Петр Викторович; Лебединский, Юрий Юрьевич; Николаев, Александр Васильевич; Курельчук, Ульяна НиколаевнаПленка кристаллического неона была конденсирована на подложке из золота и измерен спектр характеристических потерь энергии обратно рассеянных электронов (СХПЭ) при температуре 5К. Также были теоретически исследовано конденсированное ГЦК-состояние неона методами теории функционала плотности и многочастичной теории возмущений, приближения случайных фаз и уравнения Бете−Салпетера. Теоретический спектр СХПЭ был рассчитан как в приближении независимых электронов, так и с учетом многочастичных эффектов – экранирования локального поля, появления электронно-дырочных пар и связанных состояний (экситонов). Получена ширина запрещенной зоны – 21.5 эВ. Показано, что в СХПЭ неона пики потерь энергии от 17.8 до 21.5 эВ являются чисто экситонными. Кристаллическая пленка неона, являясь широкозонным диэлектриком, рассматривается как перспективный материал для имплантации Th и изучения уникального ядерного перехода в 229Th с энергией 8.2 эВ.
- ПубликацияОткрытый доступEstimation of the charge state of Th implanted in SiO2in the different atomic environment(2020) Kurelchuk, U. N.; Borisyuk, P. V.; Nikolaev, A. V.; Tkalya, E. V.; Курельчук, Ульяна Николаевна; Борисюк, Петр Викторович; Николаев, Александр Васильевич; Ткаля, Евгений Викторович© Published under licence by IOP Publishing Ltd.In this work the investigation of the charge states of thorium implanted in SiO2 is in different atomic environments and at different concentrations is presented.. Th was considered as interstitial and substitutional impurity in model cells of 6, 48 and 96 atoms. The estimations of the Bader effective charges of Th was derived from the electronic charge density n(r) calculated in DFT full relativistic PAW pseudopotential approximation. The change in the electron density of thorium due to the environment in the cells was estimated in comparison with the free atomic state.
- ПубликацияТолько метаданныеMultiple locations of boron atoms in the exohedral and endohedral C60 fullerene(2022) Bodrenko, I. V.; Bibikov, A. V.; Nikolaev, A. V.; Borisyuk, P. V.; Tkalya, E. V.; Николаев, Александр Васильевич; Борисюк, Петр Викторович; Ткаля, Евгений Викторович© 2022 American Physical Society. We study theoretically the bound states of one and two boron atoms in the exohedral and endohedral C60 fullerene. The optimal position of one boron atom is found above the midpoint of the C60 double bond in the exohedral complex, and at the center of C60 or below a carbon atom in the endohedral complex. However, the optimal position of a boron atom is often altered when the second boron atom is added to the molecular complex. For two boron atoms outside the cage the optimal arrangement is realized when the B2 molecule is attached by one boron atom to a double bond midpoint of C60 or when two boron atoms are above two double bond midpoints on opposite sides of C60. Two endohedral boron atoms can lie on the line joining either two opposite double bond midpoints or two centers of opposite pentagons. The latter case corresponds to the optimal geometry of the B2@C60 complex provided that two boron atoms are close enough to form the B2 molecule. In case one boron atom is inside while the other is outside the cage, the optimal locations of atoms are above and below two neighboring carbon atoms belonging to the same hexagon of C60. Remarkably, all these optimal arrangements have different spin states: in the exohedral complex B2C60S=1, in the endohedral B2@C60S=2 (as in the isolated B2 molecule), whereas for one boron atom inside and the other outside the cage S=0. The effective (Bader) charge of boron in these configurations varies appreciably-from 0.06e at the center of C60 to 2e in the B2C58 molecule with two boron atoms substituting for two carbon atoms in C60. We also discuss various conformations in the exohedral and endohedral molecular complexes.
- ПубликацияТолько метаданныеTwo-Photon Mechanism of the Excitation of Exciton States in Noble Gas Cryocrystals(2025) Myzin, D. A.; Borisyuk, P. V.; Gubskii, K. L.; Korneev, F. A.; Kuznetsov, A. P.; Lebedinskii, Y. Y.; Nauryzbaev, Zh. M.; Popruzhenko, S. V.; Tkalya, E. V.; Chubunova, E. V.; Shilov, V. A.; Мызин, Дмитрий Анатольевич; Борисюк, Петр Викторович; Губский, Константин Леонидович; Корнеев, Филипп Александрович; Кузнецов, Андрей Петрович; Лебединский, Юрий Юрьевич; Попруженко, Сергей Васильевич; Ткаля, Евгений Викторович; Чубунова, Елена Витальевна; Шилов, Валентин Александрович
- ПубликацияТолько метаданныеFeatures of coherent excitation of 229mTh(2022) Tkalya, E. V.; Ткаля, Евгений Викторович© 2022 Elsevier B.V.The paper studies the effects that arise at the coherent excitation of the anomalously low-lying isomeric level 3/2+(8.19±0.12 eV) in the 229Th nucleus driven by laser radiation in wide band gap dielectrics. It is shown that in such an excitation a) the appearance of additional decay channels with a width Γ of the 229mTh isomer due to electron states in the band gap leads to an effective “freezing” of the system in the ground state (the repopulation process at relatively small Γ and the Zeno effect at large Γ), making the process of nuclear excitation practically impossible, b) the probability of the α decay of a coherent superposition of the ground and isomeric states becomes equal to the half-sum of the α widths of both levels and is increased by about a factor of two in comparison with the probability of the α decay of 229Th, c) the intensity of the main α lines oscillates with the Rabi frequency and the total α spectrum shifts towards higher energies for long time measurements, d) the inverse population of nuclear levels required for the Thorium γ ray laser is achieved relatively quickly within the π pulse duration, e) the observation of the Zeno effect according to the Cook's scheme is possible for the system of three lower levels of the 229Th nucleus.