Resonant photoemission at the absorption edge of Mn and Ti and electronic structure of 1T-Mn0.2_{0.2}TiSe2_2

Resonant valence-band X-ray photoelectron spectra (ResPES) excited near 2p$_{3/2}$ core level energies, 2p X-ray photoelectron spectra (XPS) and L$_{3,2}$ X-ray absorption spectra (XAS) of Ti and Mn in single crystal of 1T-Mn$_2$TiSe$_2$ were studied for the first time. The ionic-covalent character of bonds formed by Mn atoms with the neighboring Se atoms in the octahedral coordination is established. From the XPS and XAS measurements compared with results of atomic multiplet calculations of Ti and Mn L$_{3,2}$ XAS it is found that Ti atoms are in ionic state of 4+ and Mn atoms are in the state of 2+. In ResPES of Mn$_{0.2}$TiSe$_2$ excited near Ti 2p$_{3/2}$ and Mn 2p$_{3/2}$ absorption edges the Ti 3d and Mn 3d bands at binding energies just below the Fermi level are observed. According to band structure calculations E$(\textbf{k})$ the Ti 3d states are localized in the vicinity of $\mathsf{\Gamma}$ point and the Mn 3d states are localized along the direction K-$\mathsf{\Gamma}$-M in the Brillouin zone of the crystal.Comment: 18 pages (preprint), 9 figure

Gross alpha and gross beta activity concentrations in the dust fractions of urban surface-deposited sediment in russian cities

Studies of gross alpha and gross beta activity in road-and surface-deposited sediments were conducted in three Russian cities in different geographical zones. To perform radiation measurements, new methods were applied which allow dealing with low mass and low volume dustsized (2–100 μm) samples obtained after the size fractionation procedure. The 2–10 μm fraction size had the highest gross beta activity concentration (GB)—1.32 Bq/g in Nizhny Novgorod and Rostov-On-Don, while the 50–100 μm fraction size was most prominent in Ekaterinburg. This can be attributed to the presence of radionuclides that are transferred through natural and anthropogenic processes. The highest gross alpha activity concentration (GA) in fraction sizes was found in Rostov-on-Don city within the 50–100 μm range—0.22 Bq/g. The fraction sizes 50–100 μm have a higher gross alpha activity concentration than 2–10 μm and 10–50 μm fraction sizes due to natural partitioning of the main minerals constituting the urban surface-deposited sediment (USDS). Observed dependencies reflect the geochemical processes which take place during the formation and transport of urban surface sediments. Developed experimental methods of radiation measurements formed the methodological base of urban geochemical studies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The study was supported by Russian Science Foundation (grant No. 18-77-10024). Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable

Localization of charge carriers in layered crystals MexTiSe 2 (Me = Cr, Mn, Cu) studied by the resonant photoemission

The probability of charge transfer in layered titanium diselenide between monolayers containing Cr, Mn, and Cu with different concentrations and host lattice TiSe2 is estimated according to the resonant photoemission data. For this purpose, the Raman-Auger contributions and narrow bands just below the Fermi energy were separated in the valence band spectra. These contributions provide the information about charge transfer. It is shown that the localization of the 3d electrons is typical for Cr and Cu atoms and strongly depends on theirs concentration. In MnxTiSe2, Mn 3d electrons are delocalized and the probability of the charge transfer is the greatest as compared with other compounds under investigation. © 2013 AIP Publishing LLC

Observing of Ti, Cr and Mn 2p-3d resonance in valence band of titanium dichalcogenides

Ti, Mn, Cr 2p-3d resonant photoemission for compounds with substitution of Ti atoms of host lattice by the Cr atoms CrxTi1-xSe2 and for compounds with intercalation of Mn and Cr atoms MnxTiSe2, CrxTiTe2 is studied. It is shown that the resonant behaviour depends on the geometry of survey, on 3d metal atoms lattice positions and on the magnitude and localization of atomic magnetic moment. © Published under licence by IOP Publishing Ltd

Assessment of Effective Doses Due to Inhalation of Natural Radioactivity in the Dust of Urban Environment

The inhalation exposure to dust in the urban environment for adult and child is very important due to health issues. The radionuclides Ra-226 and Th-232 were measured in the samples of urban surface deposited sediments. The average concentrations of Ra-226 and Th-232 in dust are 20.8 and 15.3 Bq kg-1, respectively. The effective dose is estimated depending on the daily activity and air dust concentration for the adult and child. The results show that the total effective dose received during 70 years by adult without outdoor activity is 0.74 μSv under exposure to air dust concentration 1×10-4 g/m3, which is typical for the city of Ekaterinburg. Critical scenario of exposure of an adult person to radioactive material in particulate matter in the air including such daily activities as training, bicycle driving and work in urban environment results in the total effective dose 17.8 μSv during 70 years at air dust concentration equal to the diurnal Maximum Permissible Limit (1.5×10-4 g/m3). Also, the critical children group can be exposed to radionuclides by inhalation through daily outdoor games, sport activity, training, bicycle etc (8 hours daily during vacation, 4 hours daily during school time, 2000 hours per year from 7 years to 17 years). The total effective dose for critical children group is 2.9 μSv. Thus, the effective doses due to inhalation of natural radioactivity in the dust in city of Ekaterinburg are relatively low in comparison ICRP reference level. © 2020 American Institute of Physics Inc.. All rights reserved

Electronic structure of Co_xTiSe_2 and Cr_xTiSe_2

The results of investigations of intercalated compounds Cr_xTiSe_2 and Co_xTiSe_2 by X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES) are presented. The data obtained are compared with theoretical results of spin-polarized band structure calculations. A good agreement between theoretical and experimental data for the electronic structure of the investigated materials has been observed. The interplay between the M3d--Ti3d hybridization (M=Cr, Co) and the magnetic moment at the M site is discussed. A 0.9 eV large splitting of the core Cr2p{3/2} level was observed, which reveals a strong exchange magnetic interaction of 3d-2p electrons of Cr. In the case of a strong localization of the Cr3d electrons (for x<0.25), the broadening of the CrL spectra into the region of the states above the nominal Fermi level was observed and attributed to X-ray re-emission. The measured kinetic properties are in good accordance with spectral investigations and band calculation results.Comment: 14 pages, 11 figures, submitted to Phys.Rev.

ELECTRONIC STRUCTURE OF FeSi

The full set of high-energy spectroscopy measurements including X-ray photoelectron valence band spectra and soft X-ray emission valence band spectra of both components of FeSi (Fe K_beta_5, Fe L_alpha, Si K_beta_1,3 and Si L_2,3) are performed and compared with the results of ab-initio band structure calculations using the linearized muffin-tin orbital method and linearized augmented plane wave method.Comment: 11 pages + 3 PostScript figures, RevTex3.0, to be published in J.Phys.:Cond.Matte

Electronic Structure of CoxTiSe2 and CrxTiSe2

The results of investigations of intercalated compounds CrxTiSe2 and CoxTiSe2 by x-ray photoelectron spectroscopy and x-ray emission spectroscopy are presented. The data obtained are compared with theoretical results of spin-polarized band-structure calculations. A good agreement between theoretical and experimental data for the electronic structure of the investigated materials has been observed. The interplay between the M 3d−Ti3d hybridization (M=Cr, Co) and the magnetic moment at the M site is discussed. A 0.9-eV large splitting of the core Cr2p3/2 level was observed, which reveals a strong exchange magnetic interaction of 3d−2p electrons of Cr. In the case of a strong localization of the Cr 3d electrons (for x&lt;0.25), the broadening of the Cr L spectra into the region of the states above the nominal Fermi level was observed and attributed to x-ray reemission. The measured kinetic properties are in good accordance with spectral investigations and band calculation results. © 2001 The American Physical Society.This work was supported by the Russian Science Foundation for Fundamental Research (Projects No. 99-03-32503 and No. 00-15-96575), a NATO Linkage Grant (No. HTECH.LG 971222), and a DFG-RFFI Project. Financial support from the Deutsche Forschungsgemeinschaft is greatly acknowledged