THEORY DEPARTMENT
Fritz Haber Institute of the Max Planck Society

All FHI Seminars

The crucial role of metal-oxide interfaces in catalysis
Speaker:Prof. Gianfranco Pacchioni
 Dipartimento di Scienza dei Materiali Università di Milano Bicocca
Time:Thursday, 20th June 2019, 11:00 AM
Location: AC Seminar Room, Building F, room 0.04
Organized: AC
Abstract: Nanoparticles deposited on an oxide support, or nanostructured oxides grown on a metal surface may result in new efficient catalysts. We will discuss in particular the high reactivity of the oxygen atoms at the boundary region between a metal cluster and the oxide surface in CO oxidation, a prototype reaction. Au nanoparticles on TiO2 and ZrO2 supports will be used to provide compelling evidence that the reaction occurs at specific sites of the Au/oxide interface and that even a non-reducible oxide such as ZrO2 can become reducible when interfaced with gold. Also the deposition of oxide ultrathin films on metals may result in completely different properties of deposited metal clusters, and recent examples of this effect will be discussed for ultrathin, graphitic-like ZnO layers on Cu, Ag, Au. Controlling the metal/oxide interface is thus essential to design new catalysts with tailored properties.

Space-Time Quantum Information in Single Molecules
Speaker: Prof. Wilson Ho
 University of California, Irvine, CA
Time:Friday, 21st June 2019, 11:00 AM
Location: Richard-Willstätter-Haus, Faradayweg 10,14195 Berlin
Organized: CP
Abstract: Heterogeneity in the mass, charge, and spin distributions is fundamental to all matter and gives rise to its distinct static and dynamic properties. Ultimately it is important to resolve this heterogeneity by measuring excitations at atomic dimensions. This spatial resolution has been achieved with inelastic electron tunneling spectroscopy and microscopy with a low temperature scanning tunneling microscope (STM). Furthermore, by coupling the STM to a femtosecond laser, it has become possible to probe matter at the space-time limit. This talk illustrates experiments in space and time to reveal two-state excitations and coherent superposition in single molecules. The vibration, spin, and charge in molecules serve as quantum sensors and carriers of quantum information. The fundamental interactions obtained from probing molecules in space and time should also be applicable to the understanding of interactions in other condensed matter systems.

Using scanning probes to fabricate and characterise nanoscale donor devices in silicon
Speaker:Dr. Neil Curson
 University College London
Time:Monday, 24th June 2019, 11:00 AM
Location: PC Seminar Room G2.06, Building G
Organized: PC
Abstract: Atomic and nano-scale structures consisting of dopants buried in silicon can be used to make novel quantum devices. The process of fabricating buried donor structures using scanning tunneling microscope-based lithography, combined with precursor gas adsorption and molecular beam epitaxy will be described. In addition, the electrical and optical characterisation of such structures will be discussed. The first characterisation technique is scanning microwave microscopy (SMM), which we demonstrate to be a non-invasive probe of the quantitative 3D spatial location and sheet conductivity of three-dimensional dopant nanostructures, buried hundreds of atomic layers below a silicon surface. Secondly we electrically characterise the terahertz response of a dilute 2D layer of phosphorus dopants, buried 15 nm below the surface of silicon. Our measurements reveal new physics about the interaction of donor Rydberg states with their local environment. Finally we expand the current device fabrication toolbox by demonstra-ting that phosphorus and arsenic co-doped nanostructured devices can be made, and discuss the potential opportunities that such devices offer.

“Exploring Confinement Effects in Supported Na-noporous Silicates”
Speaker: Dr. Anibal Boscoboinik
 Brookhaven National Laboratory
Time:Monday, 24th June 2019, 11:15 AM
Location: Faradayweg 16, Buidling P, Seminar Room
Organized: GFW

Precision spectroscopy of molecular hydrogen
Speaker: Maximilian Beyer
 Department of Physics, Yale University, New Haven, USA
Time:Friday, 5th July 2019, 2:00 PM
Location: Haber-Villa
Organized: MP
Abstract: Molecular hydrogen and its ion are the simplest of all molecules and as such are important systems for the development of molecular quantum mechanics. The rovibrational energy-level structure of these one- and two-electron systems can be calculated extremely precisely by quantum-chemical methods which include the determination of relativistic and QED effects. By comparison with the results of laser precision measurements of rovibrational intervals, fundamental constants or particle properties, such as the proton-to-electron mass ratio or the proton size, can be determined. I will discuss the spectroscopy of molecular Rydberg states in combination with Rydberg-series extrapolation using multichannel quantum-defect theory (MQDT) to determine vibrational, rotational, fine- and hyperfine-structure intervals of the molecular hydrogen ion and the dissociation energy of the hydrogen molecule. Studies of molecular Rydberg states in the vicinity of the first dissociation threshold of the molecular ions allowed the first observation of shape and Feshbach resonances of H2+, HD+ and D2+. The scheme for measuring parity violation in diatomic molecules is illustrated with the example of BaF and a similar experiment using molecular hydrogen ions is proposed, that would allow the first observation of P-violating effects in light nuclei at low energies.

TBA
Speaker:Prof. Pawel Kulesza
 University of Warsaw, Dept. of Chemistry
Time:Tuesday, 16th July 2019, 11:00 AM
Location: Faradayweg 16, Building P, Seminarr Room
Organized: GFW

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