Search

Your search keyword '"Petrov, V G"' showing total 401 results
Start Over Author "Petrov, V G"
401 results on '"Petrov, V G"'

14. Electronic Structure of NoO2.

Author

Teterin, Yu. A., Ryzhkov, M. V., Putkov, A. E., Maslakov, K. I., Teterin, A. Yu., Ivanov, K. E., Kalmykov, S. N., and Petrov, V. G.

Subjects
X-ray photoelectron spectra, CONDUCTION electrons, ELECTRONIC structure, MOLECULAR orbitals, CHEMICAL bonds
Abstract

The electronic structure of NoO2 and the valence-band X-ray photoelectron spectrum (XPS) in the energy range from 0 eV to ~40 eV are calculated by the relativistic discrete variation method. Significant covalency effects are observed in NoO2, which are due to a considerable overlap of not only No 6d AO but also No 6p and No 5f AOs with oxygen orbitals. The MO histogram and scheme are derived, which enable the comprehension of features of the chemical bond nature and the structure of the XPS spectrum of valence electrons in NoO2. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

22. Effective Actinide Ion Charges in AnO2 (An = Th‒Lr).

Author

Teterin, Yu. A., Putkov, A. E., Ryzhkov, M. V., Teterin, A. Yu., Ivanov, K. E., Kalmykov, S. N., and Petrov, V. G.

Abstract

The electronic structure of AnO2 (An = Th‒Lr) and the structure of X-ray photoelectron spectra of their valence electrons were calculated by the relativistic discrete variation method in the MO LCAO cluster approximation (molecular orbitals as linear combinations of atomic orbitals). This structure is in satisfactory agreement with the available experimental spectra. The effective charges QAn of the An ions in AnO2 were determined as the difference between the number of electrons in the neutral An atom and the number of electrons in the actinide ion in the AnO8 cluster. The dependence of the effective charges QAn in AnO2 on the atomic number Z was obtained. The estimated values in the range 0.42 e < QAn < 1.04 e differ significantly from QAn(IV) = 4 e, found in the ionic approximation. This is attributed to the significant covalence effects in AnO2, associated with the overlap of not only An6d, but also of An6p and An5f AOs with the oxygen orbitals. There is qualitative agreement between the obtained QAn values and the values of the chemical shifts (several electron-volts) of the lines of the actinide 4f core electrons in the XP spectra of dioxides relative to the metals. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

27. International Geomagnetic Reference Field: the thirteenth generation

Author

Alken, P., Thébault, E., Beggan, C. D., Amit, H., Aubert, J., Baerenzung, J., Bondar, T. N., Brown, W. J., Califf, S., Chambodut, A., Chulliat, A., Cox, G. A., Finlay, C. C., Fournier, A., Gillet, N., Grayver, A., Hammer, M. D., Holschneider, M., Huder, L., Hulot, G., Jager, T., Kloss, C., Korte, M., Kuang, W., Kuvshinov, A., Langlais, B., Léger, J.-M., Lesur, V., Livermore, P. W., Lowes, F. J., Macmillan, S., Magnes, W., Mandea, M., Marsal, S., Matzka, J., Metman, M. C., Minami, T., Morschhauser, A., Mound, J. E., Nair, M., Nakano, S., Olsen, N., Pavón-Carrasco, F. J., Petrov, V. G., Ropp, G., Rother, M., Sabaka, T. J., Sanchez, S., Saturnino, D., Schnepf, N. R., Shen, X., Stolle, C., Tangborn, A., Tøffner-Clausen, L., Toh, H., Torta, J. M., Varner, J., Vervelidou, F., Vigneron, P., Wardinski, I., Wicht, J., Woods, A., Yang, Y., Zeren, Z., and Zhou, B.

Published
2021
Full Text
View/download PDF

32. Gamma-ray dose threshold for MAPbI3 solar cells.

Author

Boldyreva, A. G., Novikov, A. V., Petrov, V. G., Zhivchikova, A. N., Tepliakova, M. M., and Stevenson, K. J.

Abstract

In this work, we report on the effects observed in MAPbI3 polycrystalline films and solar cells under moderate gamma-ray doses of 3–21 kGy. We applied several instrumental techniques such as photoluminescence spectroscopy, time-resolved photoluminescence, Suns-VOC measurement, and impedance spectroscopy to characterize exposed samples. We observed a nonlinear dependency of such characteristics as PL intensity, career lifetime, ideality factor, and recombination resistance on the exposure dose. Small doses of 3–5 kGy annihilate some of the defect centers in the material, which results in improved carrier extraction and prolonged carrier lifetime, while with larger doses of 10 kGy and above, nonradiative recombination becomes predominant. In this way, we revealed a gamma-ray threshold for MAPbI3 films of around 10 kGy, above which it is not recommended to exploit this material. In space environment, yearly doses rarely exhibit 0.1 kGy (10 krad), and the MAPbI3 material has a sufficient margin of safety for space applications. Moreover, this unusual behaviour opens up the opportunity to use gamma-ray sources as an effective method to improve the quality of defective polycrystalline perovskite films before actual exploitation in an ionizing radiation-free environment. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

44. ELECTRONIC STRUCTURE AND CHEMICAL BONDING IN EsO2.

Author

Teterin, Y. A., Ryzhkov, M. V., Putkov, A. E., Maslakov, K. I., Teterin, A. Y., Ivanov, K. E., Kalmykov, S. N., and Petrov, V. G.

Subjects
CHEMICAL bonds, CHEMICAL structure, CONDUCTION electrons, X-ray photoelectron spectra, MOLECULAR orbitals
Abstract

The density of states of valence electrons of the EsO2 dioxide is calculated by the relativistic discrete variational method. The scheme of valence molecular orbitals (MOs) is constructed taking into account the photoelectric effect cross sections of valence electrons. The histogram of X-ray photoelectron spectra (XPS) is built for the electron binding energies from 0 eV to ~40 eV. It is shown that the structure of this spectrum contains contributions of outer valence orbitals (OVMOs, from 0 eV to ~15 eV) and inner valence orbitals (IVMOs, from ~15 eV to ~50 eV) molecular orbitals. It is established that Es 5f and Es 6p electrons participate in the chemical bonding. It is established that not only Es 6d, but also Es 6p and Es 5f orbitals overlap significantly with ligand orbitals, resulting in a highly covalent chemical bonding in this dioxide. The nature of chemical bonding and the structure of the XPS spectrum of valence electrons in EsO2 is clarified using the scheme of MOs. It is shown that the chemical bonding formed by OVMO electrons is weaken by one third due to IVMO electrons. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results