Dual-Comb Spectroscopy Group

Master project: High power fiber amplifier system for high resolution spectroscopy

Project start: May 2022 - as soon as possible

Within the FWF START project ELFIS – Electronic Fingerprint Spectroscopy – we examine different molecular species of earth atmospheric relevance by means of visible and near ultraviolet absorption spectroscopy with unprecedented spectral resolution. This allows a detailed analysis of photoinduced chemical reactions like the ones that are triggered by our sun in the atmosphere (e.g. the reaction cycles including nitrous oxides and ozon). The high spectral resolution is enabled by using a novel spectroscopy method called dual comb spectroscopy. It is the combination of two stabilized femtosecond laser sources that are typically emitting in the near infrared region. In order to transfer the radiation into the visible and near ultraviolet, nonlinear processes of frequency up conversion are necessary - and with that high pulse energies are a prerequisite. The goal of this master project is the development of a unique high power fiber amplifier system delivering those highly energetic laser pulses. First spectroscopic experiments in nitrous dioxde, formaldehyde and ammonia will prove its capabilities.

Compensation: 2640 €
Contact: Assoc. Prof. Birgitta Schultze-Bernhardt


Exotic Surfaces

Master's project: Studying phase transitions of layered materials with helium scattering

The aim of this project is to study the surface structure of the transition-metal dichalcogenide (TMDC) TaS2 with helium atom scattering. TaS2 has a particularly rich phase diagram involving several charge-density wave (CDW) transitions driven by strong electronic correlations and electron-phonon coupling upon changes of the surface temperature. Helium scattering measurements at different sample temperatures should allow to follow the phase transitions and the changes upon the surface structure / charge density with temperature.

Compensation: € 2640

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Master's project: Setup of a gas dosing system for molecule/surface interaction studies

For studies of the adsorption of gas molecules on various material surfaces, so-called Dirac materials, the setup of a gas dosing system is necessary. Therefore, an existing experimental apparatus should be extended with a setup for the dosage of gases.
To deliver gas adsorbates onto the surface in a controlled and quantitative way, a gas-handling system with a microcapillary array beam will be designed and constructed. The master student will be responsible for design and setup of the gas dosing system with help provided by our group and should then run first adsorption tests on Dirac material surfaces.

Compensation: € 2640

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Koch group: Femtosecond dynamics

Master project: Femtosecond dynamics in isolated molecules Many processes in molecules take place on ultrafast (femto- and picosecond) timescales. We investigate such processes in single, isolated molecules with pump-probe femtosecond laser spectroscopy and photoelectron and photoion detection. In particular, coincidence detection of electrons and ions, the novelty of our setup, provides important information about molecular fragmentation.
The aim of this master project is to apply continuously variable excitation and/or probe wavelengths for dynamics studies in acetone molecules. The master student will work in a modern laser lab and acquire a deep insight into molecular processes and dynamics. They will be trained in the following areas: ultrafast laser science, photoelectron and photoion spectroscopy, ultra high vacuum, automated data acquisition and hardware control.
Need more information? - feel free to stop by anytime at our offices (Markus Koch: PHEG092; Pascal Heim, Bernhard Thaler: PHEG050). Compensation: 2640 €
Contact: Ass. Prof. Markus Koch

Hauser Group: Modeling of catalytic reactions on mixed-metallic particles of subnanometer size

Metal clusters with diameters in the nanometer range show outstanding chemical features which differ significantly from the bulk material. Particularly interesting is the ability to catalyse selected reactions. The aim of this diploma thesis is to study the activity and selectivity of selected materials (Au, Ag, Cu, Pt, Fe, Ni) for the adsorption and follow-up dehydrogenation of short-chained alkanes with density functional theory, starting with the evaluation of basic properties such as adsorption energies and their dependence on particle structure, composition and size. Compensation: 2640 €
Contact: Ass. Prof. Andreas Hauser

Hauser Group: Development of a neural network for metal cluster simulations

The master student will be part of a team working on NN development. He/She will be focusing on the crucial task of writing parsing scripts for the output of the selected program packages and will develop a program which translates cartesian coordinates or z-matrix geometries into so-called symmetry functions, a non-redundant input vector format for the neural network. This technically challenging part will be performed with the help of Dr. Marquetand, an experienced user and developer of NNs for chemistry applications from the University of Vienna, who offered his assistance. Compensation: 2640 €
Contact: Ass. Prof. Andreas Hauser

Hauser Group: NN development and ab initio database for metal clusters

A Master student will join the project listed above in the second half of 2017. After getting introduced to Q-Chem and quantum chemistry methods in general, it will be his task to assist with the parsing of Q-Chem output, to perform a series of benchmark ab initio calculations on small metal clusters to provide first test sets for the training of the NN, and to collaborate with the PhD students on finalizing a first draft version of the NN. Compensation: 2640 €
Contact: Ass. Prof. Andreas Hauser

Hauser group: Real-time electronic structure theory

Real-time electronic structure theory, a challenging, yet comparably less advanced subfield of computational chemistry, has gained substantially in interest in recent years due to experimental breakthroughs in the field of ultrafast spectroscopy on the atto- and femtosecond timescale. The theory aims for a realistic description and simulation of electron dynamics, by evolving either the Schrödinger equation or the Dirac equation in cases where relativistic effects become relevant.

By now, for almost all standard methods of computational chemistry there exists a time-dependent (TD) counterpart, for density- as well as wavefunction based methods, although of varying computational practicability and numerical accuracy. In the course of this master thesis, an atomic orbital-based ansatz within the real-time electronic propagation formulation will be applied to the Schrödinger equation for the electronic many-body problem. Starting from a well-known TD-Hartree-Fock framework, it is our goal to implement a cost-efficient TD-Configuration Interaction method based on the Python programming language. Somewhat challenging, but surely exciting as well ;) 

Only basic programming skills in Python are required, but advanced knowledge would be highly appreciated. It is highly recommended for the candidate to participate in the lecture "Modelling of Molecular Systems" which will be held in the winter semester. Please get in contact via mail if interested. FWF funding might be available in Summer 2023, but  can not be guaranteed yet.

Contact: Ass. Prof. Andreas Hauser