The Hauser Group

Group news and open positions



Internal coordinates meet Gaussian Process Regression

In our latest JCP article on machine learning techniques in computational chemistry we investigated the combination of well-established internal coordinate systems with Gaussian process regression for geometry optimizations of molecular systems. Typically, the latter ML approach is combined with Cartesian coordinates because it's more convenient, but with internals there is more to gain! Nice work Ralf, congratulations!

Robots shaping a NEB trajectory

Our JCTC article on machine learning-enhanced searches for transition states just came out - congratulations to Ralf and Klemens! As it turns out, Gaussian Process Regression is a very efficient and easily realized method to accelerate those costly searches we all know too well... Next time, let our little robots help you find your reaction path! We hope to have this implemented soon in Q-Chem.

Robots shaping a NEB trajectory

Our collaboration with the group of María Pilar de Lara-Castells at the C.S.I.C. Madrid led to a publication in JPCC on the ability of sub-nanometer-sized Cu5 particles on TIO2 to activate carbon dioxide. Maybe this can be combined somehow with the enhanced photoadsorption we found for the same material (see here) for photocatalysis with sunlight!

FeAu graphics

What does the spectroscopy of helium-immsered molecules have to do with questions concerning the origin of life in the universe ?

Find out by reading the comment of Dr. de Lara-Castells and myself on the review article of Barone and Puzzarini published in Elsevier's Physics of Life Reviews.

FeAu graphics

Rusting on the nanoscale: In a joint effort with the Ernst group we could determine the number of atomic layers of gold necessary to protect a Fe nanoparticle from oxidation, see our mixed theory/experimental article in Nanoscale Advances.

TiO2 TOC graphics

Yet another team success! Together with the Ernst group we could show that solid vanadium pentoxide evaporates preferably in units of (V2O5)2 when heated. This means that the stoichiometry is not affected and might open new ways of nanostructure coating with this SCR catalyst.

Have a look at our latest publication in RSC Chemical Science. We even made it to the back cover of the issue!
TiO2 TOC graphics
Our collaboration with the group of María Pilar de Lara-Castells at the C.S.I.C. Madrid and the NANOMAG-team of Manuel Arturo Lopez-Quintela at the University of Santiago de Compostela on smallest copper clusters and their effect on the optical properties of TiO2 led to a publication in ACS Journal of Materials Chemistry A! The highly stable Cu5 clusters enhance the adsorption of photons and shift the absorption spectra towards the visible. This is a big step forward towards harvesting solar energy for follow-up surface reactions; maybe we can link this to some relevant photocatalysis in the next step.
femto text
With joint forces to Nature Communications! What is really going on if you excite an atom inside a quantum solvent? Find out by clicking the link above. We congratulate the team of Prof. Koch on their recent experimental success and are very happy that we could contribute a little theory to this breakthrough. See the press release for more information!
Johannes Cartus smiling in front of his poster
Our team is back from the "Computational Chemistry meets Artificial Intelligence" or CC2AI meeting 2018 in Lausanne, where Ralf was giving a talk and Klemens, Alexander and Johannes were presenting their posters. Great news: Johannes Cartus won the poster prize for the presentation of his work on "A Neural Network based approach towards SCF guesses". Was it the jacket? Anyway, congratulations!
Finally, we could dedicate some time again to our work on chiral separation via 2D membranes. A follow-up study in Chem.Phys.Chem. on candidate materials and computatational strategies to estimate selectivities just went online. In the figure you see an approximate reaction pathway for a benchmarking scenario, the propagation of ethane through a graphene pore, evaulated with different methods. We also tested the new tight-binding program of the Grimme group, see here for details.
Our invention (patent pending, inventors A. Hauser and M. Koch), developed in a little side project, was awarded 2nd prize at the PHOENIX meeting in Salzburg. It's a machine for the separation of precious materials from waste, applicable to particles with diameters below one mm. Okay, that's not nanoparticles, but it can't be always "nano", can it?
AgAu core-shell nanoparticles
And yet another team success! This article on the structural inversion of NiAu core-shell nanoparticles upon heating and follow-up cooling has just been published at ACS Chemistry of Materials. Our research efforts are slowly invading the highly competitive nanomaterials sector! In this case, the alloying processes is enhanced by the presence of oxygen, which is also responsible for locking the particles in an oxidized nickel-shell and gold-core after a heating cycle.
AgAu core-shell nanoparticles
Sucess! Our long-term collaboration with the Ernst group and the FELMI on mixed-metallic nanoparticles led to a publication in RSC Nanoscale. Have a look at our results for the AgAu core-shell system. We study alloying processes in Ag@Au and Au@Ag particles with average radii of 2 nm and measure the the temperature-dependent diffusion constant at the nanoscale.
C60 in He
We could finally solve the puzzle about the interaction of C60 with Cs2 in superfluid helium! It is indeed a harpoon-type reaction where the electron is stolen by the fullerene. This is only possible for Cs2, where the crossing point of the ionic and the neutral PES takes place already at larger distances. For more details, please see our latest article in JPC Letters!
This is something that caught out interest many years ago: The possibility of forming Rydberg superatoms via excitation of alkali atoms on He droplets. In this article we develop a new ansatz to make predictions for quantum numbers where a migration of the alkali atom into the droplet should become feasible while its valence electron still keeps spinning around the He droplet.
Samuel Frühwirth defended his Master Thesis today, shining with a flawless talk and a sparkling performance in the exams. Congratulations Samuel, and good luck for all your future undertakings. We already miss your tongue-in-cheek approach to everything!
In a nice collaboration with Wolfgang Ernst and his group we developed a method to describe surface-diffusion processes in metallic nanostructures . Please have a look at the outcome of our joint efforts:

A coarse-grained Monte Carlo approach to diffusion processes in metallic nanoparticles (EPJD)

Thermally induced breakup of metallic nanowires: Experiment and theory (PCCP)

He and N2 in a CNT
Our collaboration with the CSIC in Madrid is on fire! The third article of our series on He-interacting carbon structures has just been published at JPCC! It contains a more detailed study of the vibrational motion of He atoms inside a carbon nanotube and compares it to that of molecular nitrogen.
C60 in He
Our PCCP article on the interaction of C60 with Cs2 in superfluid helium made it online! This study was triggered by recent experiments of Paul Scheier and Andrew E. Ellis. It seems that a minimal charge transfer must occur despite the embedding in superfluid helium. The quenching lets Cs2 react but prevents a single Cs atom from approaching the fullerene.
nanotube in He
Our JPC Letter on carbon nanotubes immersed in superfluid helium got accepted! The tubes show a fascinating quantum phenomenon: They sink into the liquid but are only partly flooded, resembling an onion-like structure of He layers inside the tube due to zero-point energy effects. The size of the tube diameter determines the number of layers that fit into the tube, causing an axial cavity in some cases. Cool?
The PiR project is on the news now, see People seem to like Mozartkugeln. I am glad we did not take Toffifee or Raffaello. It was a tough call though.
Good news again! We also got funding for our project "Heterogeneous catalysis on metallic nanoparticles: Force field development based on machine learning" from the FWF! This is a good month indeed...
WKO winner pic
We got a prestigious 'Partnership in Research'-Grant for our project on Nano-Mozartkugeln ! The Partnership in Research (PiR) programme of the Christian Doppler Gesellschaft is designed to encourage new partnerships between research and the business world, see here for more info. It's a one-off programme carried out in cooperation with the FWF. It's going to be a tight collaboration with the Ernst group. We are looking for PhD and master students now, please scroll down for more info.
Ralf Meyer defended his Master Thesis today and gave a stunning performance. Congratulations Ralf, very impressive!
WKO winner pic
The Graphene Science Handbook is out, and with it our contribution! CRC managed to publish the 6-book series finally. Check out chapter 25 of the third book!
WKO winner pic
Samuel Frühwirth won a scholarship from the WKO (Wirtschafts- kammer Österreich) for his ongoing diploma thesis project entitled "Development of a novel, membrane-based method for chiral separation in the pharmaceutical industries". Congratulations!
WKO winner pic
Our PCCP article on the dehydrogenation of alkanes over bimetallic nanoparticles went online today.

Open positions...

Open positions in joint projects...

Note that, in contrast to all theory positions listed above, the ones given below are mostly experimental , and will be co-supervised by Prof. Wolfgang Ernst.

June 2018: Master thesis - Catalysis on mixed-metallic subnanometer-sized particles
The helium-droplet technique is used to create our `Nano-Mozartkugeln', which are mixed-metallic clusters of Au and Cu with diameters in the nanometer range. The particles are then deposited on supports of amorphous carbon or SiO2. The results are checked by electron microscopy imaging with the help of our colleagues at the FELMI-ZFE. A newly designed reaction chamber has to tested for leaks and for the accessible temperature range given by the built-in sample heater. After that, first BET adsorption measurements of nitrogen gas are planned. Finally, a selection of materials is then placed into the reaction chamber and exposed to a He-diluted mixture of butadiene, propene and hydrogen for a series of temperature-controlled reaction measurements. Gas composition during reaction will be monitored by the quadrupole mass spectrometer attached to the chamber.
Maintained by Andreas Hauser | Last updated Feb 2020 | Impressum