The Long Journey from Ab Initio Calculations to Density Functional Theory for Nuclear Large Amplitude Collective Motion

At present there are two vastly different ab initio approaches to the description of the the many-body dynamics: the Density Functional Theory (DFT) and the functional integral (path integral) approaches. On one hand, if implemented exactly, the DFT approach can allow in principle the exact evaluation of arbitrary one-body observable. However, when applied to Large Amplitude Collective Motion (LACM) this approach needs to be extended in order to accommodate the phenomenon of surface-hoping, when adiabaticity is strongly violated and the description of a system using a single (generalized) Slater determinant is not valid anymore. The functional integral approach on the other hand does not appear to have such restrictions, but its implementation does not appear to be straightforward endeavor. However, within a functional integral approach one seems to be able to evaluate in principle any kind of observables, such as the fragment mass and energy distributions in nuclear fission. These two radically approaches can likely be brought brought together by formulating a stochastic time-dependent DFT approach to many-body dynamics.Comment: 9 page

Some open questions in TDDFT: Clues from Lattice Models and Kadanoff-Baym Dynamics

Two aspects of TDDFT, the linear response approach and the adiabatic local density approximation, are examined from the perspective of lattice models. To this end, we review the DFT formulations on the lattice and give a concise presentation of the time-dependent Kadanoff-Baym equations, used to asses the limitations of the adiabatic approximation in TDDFT. We present results for the density response function of the 3D homogeneous Hubbard model, and point out a drawback of the linear response scheme based on the linearized Sham-Schl\"uter equation. We then suggest a prescription on how to amend it. Finally, we analyze the time evolution of the density in a small cubic cluster, and compare exact, adiabatic-TDDFT and Kadanoff-Baym-Equations densities. Our results show that non-perturbative (in the interaction) adiabatic potentials can perform quite well for slow perturbations but that, for faster external fields, memory effects, as already present in simple many-body approximations, are clearly required.Comment: 15 pages, submitted to Chemical Physic

The electronic structure of iridium oxide electrodes active in water splitting

Iridium oxide based electrodes are among the most promising candidates for electrocatalyzing the oxygen evolution reaction, making it imperative to understand their chemical/electronic structure. However, the complexity of iridium oxide's electronic structure makes it particularly difficult to experimentally determine the chemical state of the active surface species. To achieve an accurate understanding of the electronic structure of iridium oxide surfaces, we have combined synchrotron-based X-ray photoemission and absorption spectroscopies with ab initio calculations. Our investigation reveals a pre-edge feature in the O K-edge of highly catalytically active X-ray amorphous iridium oxides that we have identified as O 2p hole states forming in conjunction with IrIII. These electronic defects in the near-surface region of the anionic and cationic framework are likely critical for the enhanced activity of amorphous iridium oxides relative to their crystalline counterparts

Brottsofferklander: Har bedömarens kön samt våldtäktsoffrets kön och alkoholhalt betydelse?

Våldtäktsoffer kan ibland klandras för vad de utsatts för, så kallat offerklander. I en experimentell studie med designen 2 (Bedömarens kön: man vs. kvinna) × 2 (Offrets kön: man vs. kvinna) × 2 (Offrets alkoholhalt: nykter vs. berusad) fick 275 juriststudenter runt om i Sverige genom en webbenkät ta del av en vinjett av ett fiktivt våldtäktsfall för att sedan utdela grad av skuld. Några av hypoteserna var att manliga bedömare skulle skuldbelägga i större utsträckning samt att manliga samt berusade offer skulle skuldbeläggas i större utsträckning. Studien visade inget stöd för hypoteserna då inga signifikanta skillnader upptäcktes mellan grupperna. Trots förekomsten av mindre metodologiska betänksamheter bidrar studien till vidare förståelse för under vilka omständigheter offerklander uppstår