Role of Quantum-size Effects on the Dehydrogenation of CH4 on 3d TMn Clusters: DFT Calculations Combined with Data Mining

In this work, we report a theoretical investigation of the role of quantum-size effects (QSE) on the dehydrogenation of methane (CH4) on 3d transition-metal clusters, TMn , where TM =...

Quantum Size Effects Arising from Nanocomposites Physical Doping with Nanostructures Having High Electron Affinit

This article considers main problems in application of nanostructured materials in high technologies. Theoretical development and experimental verification of methods for creating and studying the properties of physically doped materials with spatially inhomogeneous structure on micro and nanometer scale are proposed. Results of studying 11 quantum size effects exposed to nanocomposites physical doping with nanostructures with high electron affinity are presented. Theoretical and available experimental data were compared in regard to creation of nanostructured materials, including those with increased strength and wear resistance, inhomogeneous at the nanoscale and physically doped with nanostructures, i.e., quantum traps for free electrons. Solving these problems makes it possible to create new nanostructured materials, investigate their varying physical properties, design, manufacture and operate devices and instruments with new technical and functional capabilities, including those used in the nuclear industry. Nanocrystalline structures, as well as composite multiphase materials and coatings properties could be controlled by changing concentrations of the free carbon nanostructures there. It was found out that carbon nanostructures in the composite material significantly improve impact strength, microhardness, luminescence characteristics, temperature resistance and conductivity up to 10 orders of magnitude, and expand the range of such components’ possible applications in comparison with pure materials, for example, copper, aluminum, transition metal carbides, luminophores, semiconductors (thermoelectric) and silicone (siloxane, polysiloxane, organosilicon) compounds

Electron confinement meet electron delocalization: non-additivity and finite-size effects in the polarizabilities and dispersion coefficients of the fullerenes

Unique dichotomy of electron confinement and delocalization yields non-additive quantum-size effects in the polarizabilities and dispersion coefficients of the fullerenes.

Исследование фотофизических свойств нанокомпозита HgI-=SUB=-2-=/SUB=-@mSiO-=SUB=-2-=/SUB=-

The luminescent properties of a composite consisting of mesoporous silica and mercury diiodide nanoparticles formed in silica nanopores have been investigated. The formation of nanoparticles was carried out by evaporation of a HgI2 solution introduced into the SiO2 nanopores. It was found that photoluminescence of the HgI2@mSiO2 composite was due to emission of mercury diiodide, with the emission spectrum being significantly shifted towards shorter wavelengths with respect to the emission spectrum of bulk HgI2 crystals. The shift of the HgI2 emission spectrum to the short-wavelength side is explained by quantum-size effects in the electronic spectra of HgI2 nanoparticles included in the composite. The significant width of the spectrum is explained by its inhomogeneous broadening due to the dependence of the band gap of the nanodots on their size d. The shape of the size distribution function of HgI2 nanodots was estimated and it was shown that it was characterized by a rather narrow maximum at dM = 2.2 nm, which is 2/3 of the diameter of the nanopores in the SiO2 matrix (~3 nm).

Landauer’s Principle in a Quantum Szilard Engine without Maxwell’s Demon

Quantum Szilard engine constitutes an adequate interplay of thermodynamics, information theory and quantum mechanics. Szilard engines are in general operated by a Maxwell’s Demon where Landauer’s principle resolves the apparent paradoxes. Here we propose a Szilard engine setup without featuring an explicit Maxwell’s demon. In a demonless Szilard engine, the acquisition of which-side information is not required, but the erasure and related heat dissipation still take place implicitly. We explore a quantum Szilard engine considering quantum size effects. We see that insertion of the partition does not localize the particle to one side, instead creating a superposition state of the particle being in both sides. To be able to extract work from the system, particle has to be localized at one side. The localization occurs as a result of quantum measurement on the particle, which shows the importance of the measurement process regardless of whether one uses the acquired information or not. In accordance with Landauer’s principle, localization by quantum measurement corresponds to a logically irreversible operation and for this reason it must be accompanied by the corresponding heat dissipation. This shows the validity of Landauer’s principle even in quantum Szilard engines without Maxwell’s demon.