Acoustic phonon impact on the inter-Coulombic decay process in charged quantum dot pairs

ABSTRACT

Recently, highly accurate multi-configuration time-dependent Hartree electron dynamics calculations demonstrated the efficient long-range energy transfer inter-Coulombic decay (ICD) process to happen in charged semiconductor quantum dot (QD) pairs. ICD is initiated by intraband photoexcitation of one of the QDs and leads to electron emission from the other within a duration of about 150 ps. On the same time scale electronically excited states are reported to relax due to the coupling of electrons to acoustic phonons. Likewise, phonons promote ionisation. Here, the QDs' acoustic breathing mode is implemented in a frozen-phonon approach. A detailed comparison of the phonon effects on electron relaxation and emission as well as on the full ICD process is presented, which supports the previous empirical finding of ICD being the dominant decay channel in paired QDs. In addition the relative importance of phonon–phonon, phonon–electron and electron–electron interaction is analysed.     

Intermolecular interactions between natural humic substances and tricyclic antidepressants

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Trimetallic NiCoM catalysts (M = Mn,Fe, Cu) for methane conversion into synthesis gas

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The Bergman kernel for the Vekua equation

The paper extends some well-known results for analytic functions onto solutions of the Vekua equation $\partial \overline{{}_z}W=aW+b\overline{W}$ regarding the existence and construction of the Bergman kernel and of the corresponding Bergman projection operator.     

Real-Space Interpretation of Interatomic Charge Transfer and Electron Exchange Effects by Combining Static and Kinetic Potentials and Associated Vector Fields**

Intricate behaviour of one-electron potentials from the Euler equation for electron density and corresponding gradient force fields in crystals was studied. Channels of locally enhanced kinetic potential and corresponding saddle Lagrange points were found between chemically bonded atoms. Superposition of electrostatic and kinetic potentials and electron density allowed partitioning any molecules and crystals into atomic - and potential-based -basins; -basins explicitly account for the electron exchange effect, which is missed for -ones. Phenomena of interatomic charge transfer and related electron exchange were explained in terms of space gaps between zero-flux surfaces of - and -basins. The gap between - and -basins represents the charge transfer, while the gap between - and -basins is a real-space manifestation of sharing the transferred electrons caused by the static exchange and kinetic effects as a response against the electron transfer. The regularity describing relative positions of -, -, and - basin boundaries between interacting atoms was proposed. The position of -boundary between - and -ones within an electron occupier atom determines the extent of transferred electron sharing. The stronger an H⋅⋅⋅O hydrogen bond is, the deeper hydrogen atom's -basin penetrates oxygen atom's -basin, while for covalent bonds a -boundary closely approaches a -one indicating almost complete sharing of the transferred electrons. In the case of ionic bonds, the same region corresponds to electron pairing within the -basin of an electron occupier atom.     

Metastable states in high carbon C–(Fe,Ni, Co) films obtained by three-electrode ion-plasma sputtering

Abstract

The effect of ion-plasma deposition on the structure of high-carbon films (at. %) Fe–(20–84) % С, Co–(5–52) % С, Ni–(7–61) % С was investigated. The lattice periods and crystallite sizes of nonequilibrium phases in the as-deposited state and after heating are determined. The temperatures of the beginning and end of the decay of metastable phases during heating at a constant speed are established. The transition from an amorphous to an equilibrium crystalline state in Fe–C films passes through the stage of formation and subsequent decomposition of an intermediate, metastable hcp phase of variable composition. The electrical and hysteretic magnetic properties of the films were measured in the as-deposited state and after heat treatment. The compositions and conditions for producing films with low values of the temperature coefficient of electrical resistance and high coercive force are established. Thus, high-carbon films of Ni–61% C in the as-depoteted state and Fe–69% C films after heating to 900?K are characterized by small TCR values (± 10^?6 К^?1) over a wide temperature range.     

Two Types of σ-Allenyl Complexes from Reactions of Silylenes and Germylenes with Chromium Fischer Alkynyl(alkoxy)carbenes

The reactivity of amidinatotetrylenes of the type E(tBu₂bzm)R¹ (E=Si, Ge; tBu₂bzm=N,N′-bis(tertbutyl)benzamidinate; R¹=alkyl or aryl) with the chromium Fischer alkynylcarbene complexes [Cr{C(OEt)C₂R²}(CO)₅] (R²=Ph; ferrocenyl, Fc) has been studied. At room temperature, two different reaction pathways have been identified: (a) attack of the amidinatotetrylene to the alkynyl C² atom (γ-attack), which leads to σ-allenyl complexes in which the original C_carbene atom maintains its attachment to the Cr(CO)₅ and OEt groups (compounds 3 ), and (b) attack of the amidinatotetrylene to the C_carbene atom (α-attack), which ends in σ-allenyl complexes in which the original C_carbene atom is not attached to the metal atom and has been inserted into an E−N bond of the amidinatotetrylene forming an E-C-N-C-N five-membered ring (compounds 4 ). It has been found that compounds 3 are thermodynamically less stable than their corresponding 4 isomers and that some of the former (E=Ge; R¹=CH₂SiMe₃) can be transformed into the latter upon heating. At high temperatures (>70 °C) the reactions involving bulky amidinatotetrylenes (R¹=Mes, tBu) end in the carbene-substitution products [Cr{E(tBu₂bzm)R¹}(CO)₅].     

Hierarchical structure of SERS substrates possessing the silver ring morphology

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Synthesis and rheological properties of star-shaped polydimethylsiloxanes based on carbosilane dendrimers

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