Optical properties of lowest-energy carbon allotropes from the first-principles calculations

We study the optical properties of lowest-energy carbon allotropes in the infrared, visible and ultra-violet ranges of light in the general gradient approximation of the density functional theory. In our calculations we used the all-electron approach as well as the pseudo-potential approximation. In the infrared range, the complex dielectric functions, infrared and Raman spectra have been calculated using CRYSTAL14 program. The electronic properties and energy-dependent dielectric functions in the visible and ultraviolet ranges have been calculated using VASP program. We have described with a good accuracy experimentally known optical properties of cubic diamond crystal. Using obtained set of relevant parameters for calculations, we have predicted optical constants, dielectric functions and Raman spectra for the lowest-energy hypothetical carbon allotropes and lonsdaleite.Comment: 11 pages, 7 tables, 5 figures, to be published in Computer Optic

Prediction of new sp3 silicon and germanium allotropes from the topology-based multiscale method

This article continues our recent publication [I.A. Baburin and D.M. Proserpio and V.A. Saleev and A.V. Shipilova, Phys. Chem. Chem. Phys.17, 1332 (2015)] where we have presented a comprehensive computational study of sp3 carbon allotropes based on the topologies proposed for zeolites. Here we predict six new silicon and six new germanium allotropes which have the same space group symmetries and topologies as those predicted earlier for the carbon allotropes, and study their structural, elastic, vibrational, electronic and optical properties.Comment: 16 pages, 16 figures, 5 tables, supplementary fil

New mechanisms for double charmed meson production at the LHCb

We discuss production of $D^0 D^0$ (and ${\bar D}^0 {\bar D}^0$) pairs related to the LHCb Collaboration results for $\sqrt{s}$ = 7 TeV in proton-proton scattering. We consider double-parton scattering (DPS) mechanisms of double $c \bar c$ production and subsequent $cc \to D^{0}D^{0}$ hadronization as well as double $g$ and mixed $g c\bar c$ production with $gg \to D^{0}D^{0}$ and $gc \to D^{0}D^{0}$ hadronization calculated with the help of the scale-dependent hadronization functions of Kniehl et al. Single-parton scattering (SPS) mechanism of digluon production is also taken into account. We compare our results with several correlation observables in azimuthal angle $\varphi_{D^{0}D^{0}}$ between $D^{0}$ mesons or in dimeson invariant mass $M_{D^{0}D^{0}}$. The inclusion of new mechanisms with $g \to D^{0}$ fragmentation leads to larger cross sections, than when including only DPS mechanism with standard scale-independent $cc \to D^{0}D^{0}$ fragmentation functions. Some consequences of the presence of the new mechanisms are discussed. In particular a larger $\sigma_{eff}$ is needed to describe the LHCb data. There is a signature that $\sigma_{eff}$ may depend on transverse momentum of $c$ quarks and/or $\bar c$ antiquarks.Comment: 16 pages, 6 figure

B-meson production in the Parton Reggeization Approach at Tevatron and the LHC

We study the inclusive hadroproduction of $B^0$, $B^+$, and $B_s^0$ mesons at leading order in the parton Reggeization approach using the universal fragmentation functions extracted from the combined $e^+e^-$ annihilation data from CERN LEP1 and SLAC SLC colliders. We have described $B$-meson transverse momentum distributions measured in the central region of rapidity by the CDF Collaboration at Fermilab Tevatron and CMS Collaboration at LHC within uncertainties and without free parameters, applying Kimber-Martin-Ryskin unintegrated gluon distribution function in a proton. The forward $B$-meson production ($2.0<y<4.5$) measured by the LHCb Collaboration also has been studied and expected disagreement between our theoretical predictions and data has been obtained.Comment: 17 pages, 11 figures. arXiv admin note: substantial text overlap with arXiv:1410.713

Heavy quark production at the LHC in the Parton Reggeization Approach

We present the general introduction to the Parton Reggeization Approach and discuss some new results on large-$p_T$ production for heavy quarks at the LHC. We concentrate here on study of different correlation spectra for $b\bar b-$jet pairs, $D\bar D-$meson pairs and $DD-$meson pairs

Щастя як філософсько-етична категорія: трансформація розуміння від давнини до сучасності

Шипілова, О. Е. Щастя як філософсько-етична категорія: трансформація розуміння від давнини до сучасності = Happiness as a philosophical and ethical category: the transformation of understanding from antiquity to the present times / О. Е. Шипілова, О. О. Гончарова // Матеріали ІІІ всеукр. студ. наук.-практ. конф. "Філософські та культурологічні проблеми людства очима студентства. – Миколаїв : НУК, 2020. – С. 88–92.У даній статті розглянуто філософське поняття «щастя», його визначення, та розуміння у різні епохи людства. Евдемонізм постає як сенс життя у філософії. З’ясовано становлення та розвиток категорії щастя від давнини до сьогодення.This article examines the philosophical concept of happiness, its definition. The concept of happiness and its understanding in different epochs of humanity are analyzed. Eudemonism is observed as the meaning of life in Philosophy. The process of gaining happiness from Antiquity to the present times is discovered.В этой статье рассмотрены философское понятие счастья, его определение. Проанализировано понятие «счастье» и его понимание в разные эпохи развития человечества. Эвдемонизм рассматривается как смысл жизни в философии. Прослеживается становление категории счастья от древности до современности