Elektronische Wechselwirkung zwischen aufgedampften Germaniumfilmen und Sauerstoff

Ge films of thicknesses within the p-boundary layer thickness are precipitated under ultra high vacuum conditions, at 77 °K. They are investigated either in the disordered state (before annealing at a higher temperature) or in the ordered state (after annealing). The electric resistance R and the photoelectric work function & are measured before and after the influence of known amounts of oxygen. R is plotted as a function of time and coverage n, Φ as a function of n. Small amounts of oxygen cause R to increase without changing Φ, large amounts result in a succeeding decrease of R and cause Φ to increase by 0.1 to 0.2 V. The results are discussed by means of a band model. At small coverages oxygen acts as an electron donator, at higher coverages as an electron acceptor. © 1963, Walter de Gruyter. All rights reserved

Exploring the Early Time Behavior of the Excited States of an Archetype Thermally Activated Delayed Fluorescence Molecule

Optical pump–probe techniques allow for an in-depth study of dark excited states. Here, we utilize them to map and gain insights into the excited states involved in the thermally activated delayed fluorescence (TADF) mechanism of a benchmark TADF emitter DMAC-TRZ. The results identify different electronic excited states involved in the key TADF transitions and their nature by combining pump–probe and photoluminescence measurements. The photoinduced absorption signals are highly dependent on polarity, affecting the transition oscillator strength but not their relative energy positions. In methylcyclohexane, a strong and vibronically structured local triplet excited state absorption (3LE → 3LE n ) is observed, which is quenched in higher polarity solvents as 3CT becomes the lowest triplet state. Furthermore, ultrafast transient absorption (fsTA) confirms the presence of two stable conformers of DMAC-TRZ: (1) quasi-axial (QA) interconverting within 20 ps into (2) quasi-equatorial (QE) in the excited state. Moreover, fsTA highlights how sensitive excited state couplings are to the environment and the molecular conformation

First Principles Calculations of Fe on GaAs (100)

We have calculated from first principles the electronic structure of 0.5 monolayer upto 5 monolayer thick Fe layers on top of a GaAs (100) surface. We find the Fe magnetic moment to be determined by the Fe-As distance. As segregates to the top of the Fe film, whereas Ga most likely is found within the Fe film. Moreover, we find an asymmetric in-plane contraction of our unit-cell along with an expansion perpendicular to the surface. We predict the number of Fe 3d-holes to increase with increasing Fe thickness on $p$-doped GaAs.Comment: 9 pages, 14 figures, submitted to PR

Instruments operations, science and innovation in expedition support: EuroMoonMars-Etna campaign 2021

Instrumentatio

EuroMoonMars Etna Campaign 2021: logistics and mission protocol

Science Communication and Societ