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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Евгений Викторович
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- ПубликацияТолько метаданныеA Unique System for Registering One-Photon Signals in the Ultraviolet Range from An Isomeric 229mTh Nucleus Implanted on Thin SiO2/Si Films(2020) Lebedinskii, Y. Y.; Borisyuk, P. V.; Chubunova, E. V.; Kolachevsky, N. N.; Vasiliev, O. S.; Tkalya, E. V.; Лебединский, Юрий Юрьевич; Борисюк, Петр Викторович; Чубунова, Елена Витальевна; Васильев, Олег Станиславович; Ткаля, Евгений Викторович© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimCurrently, an urgent task related to creating a nuclear frequency standard is the identification of a low-lying nuclear state in the thorium-229 isotope. Herein, a method for measuring the single-photon energy during the decay of an isomeric thorium-229 nucleus implanted in a wide-gap dielectric SiO2 (Eg = 9 eV) is developed. The proposed method utilizes thin silicon oxide layers obtained by thermal oxidization of the pure silica wafers, which allows measurement of the energy of photons in the ultraviolet (UV) range using an electronic spectrometer. The modeling study of electronic state excitation is provided via UV radiation from Kr, Xe, and D resonance discharging lamps. The obtained spectra are analyzed, and a method for determining the UV photon's energy is proposed.
- 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.
- 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.
- 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.
- ПубликацияТолько метаданныеSpectroscopic Studies of Crystalline Neon Film Grown on a Gold Surface(2022) Kurelchuk, U. N.; Borisyuk, P. V.; Chubunova, E. V.; Domashenko, M. S.; Kolachevsky, N. N.; Lebedinskii, Yu. Yu.; Myzin, D. A.; Nikolaev, A. V.; Tkalya, E. V.; Курельчук, Ульяна Николаевна; Борисюк, Петр Викторович; Чубунова, Елена Витальевна; Лебединский, Юрий Юрьевич; Мызин, Дмитрий Анатольевич; Николаев, Александр Васильевич; Ткаля, Евгений Викторович
- 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 метаданныеSpectroscopic studies of solid Ar condensed on a gold surface(2022) Karazhanov, S. Z.; Kurelchuk, U. N.; Borisyuk, P. V.; Chubunova, E. V.; Kolachevsky, N. N.; Lebedinskii, Y. Y.; Myzin, D. A.; Nikolaev, A. V.; Tkalya, E. V.; Курельчук, Ульяна Николаевна; Борисюк, Петр Викторович; Чубунова, Елена Витальевна; Лебединский, Юрий Юрьевич; Мызин, Дмитрий Анатольевич; Николаев, Александр Васильевич; Ткаля, Евгений Викторович© 2021 Elsevier B.V.We have studied condensed solid argon films on a gold surface, measuring its reflected electron energy-loss spectra (REELS) and X-ray photoelectron spectra (XPS) at the temperatures 5 K and 20 K. We have also reproduced theoretically the REELS considering both face-centered cubic (FCC) and hexagonal close-packed (HCP) lattices of solid argon using density-functional theory (DFT), GW approximation, random-phase approximation (RPA) and the Bethe–Salpeter equation (BSE). In the calculations the local-field dielectric screening, quasiparticles, and excitonic effects have been taken into account. The excitonic peaks in the REELS appear at ∼12 eV whereas the calculated electronic bandgap amounts to 14.3–14.4 eV for both the FCC and HCP lattices. Our results show that a solid argon film is a wide-gap dielectric best suited for implanting Th and studying its low-lying nuclear transition in 229Th with the energy of 8.2 eV.
- 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 метаданныеCumulative loading of the ion trap by laser ablation of thorium target in buffer gas(2020) Khabarova, K. Yu.; Kolachevsky, N. N.; Derevyashkin, S. P.; Borisyuk, P. V.; Strelkin, S. A.; Tkalya, E. V.; Tregubov, D. O.; Tronin, I. V.; Yakovlev, V. P.; Борисюк, Петр Викторович; Ткаля, Евгений Викторович; Трегубов, Дмитрий Олегович; Тронин, Иван Владимирович; Яковлев, Валерий Петрович© 2020 Astro Ltd Printed in the UKWe describe a method that allows accumulation in a Paul trap of a large number of ions obtained from multiple laser ablation pulses, and therefore solving the problem of a single pulse that usualy gives rise to final trapping of too few ions. The proposed method of the cumulative trap loading was based on interaction with a buffer gas that provided a friction force. The method was applied to triply charged thorium ions and trapped a total of 106 ions. Numerical analysis of the ion motion allowed the experimental parameters to be optimized for the most effective implementation of the technique.
- 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.