USA, Chemie

As part of my PhD in theoretical chemistry in Prof. Barbara Kirchner’s team at the University of Bonn, I am investigating the behaviour of liquids on solid surfaces and within nanoporous materials, such as carbon nanotubes or MOFs (metal organic frameworks). The main aim is to better understand the molecular packing behaviour and dynamic properties of liquids near the surface or within nanopores.

One objective of this research work is to develop new supercapacitors which are a further development of conventional electrochemical double-layer capacitors. Additional energy storage effects are achieved by adapting the pore size of the electrodes to the size of the ions in the electrolytes to increase the capacity. This entails fundamental research geared towards acquiring a comprehensive understanding of the effects of this energy storage and using it as a template for future components.

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The UCSD Library

I primarily use classical and ab initio molecular dynamics simulations to describe the motion and arrangement of the electrolyte molecules. I subsequently evaluate these simulations using a software program that I am actively developing, among other things.

Prof. Paesani’s research team at the University of California, San Diego is focused in particular on developing new methods for the purposes of modelling liquids. The ‘MB-pol’ force field, which is used to model water, is particularly well known. This force field centres on a new approach, the so-called many-body approach. The interaction energy of one, two and three water molecules interacting with each other in different con-figurations is calculated very precisely (at CCSD[T] level) in order to train a machine learning process. Using an additional term for the static electricity makes it possible to describe the behaviour of water at the molecular level very precisely across the entire phase diagram.

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At Yosemite Park

At the start of my stay at UC San Diego, Prof. Paesani introduced me to the research team and I was given an opportunity to present my research to date. The other PhD students gave me plenty of help over the course of the following days to get me started and give me a detailed understanding of the methodology. It was great being allowed to take part in weekly meetings for the ongoing development of the model, enabling me to gain further insights into the methodology’s background.

My project was and is to investigate the behaviour of water in carbon nanotubes of different sizes. To that end, I conducted a wide array of different simulations over the weeks and further improved the systems studied. I learned new techniques for this over that period. The plan is to publish the results of the studies in a paper, but the research work is not yet complete.

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Visiting Grand Canyon

In addition to the main project, I found the interaction with the other PhD students to be incredibly valuable. Prof. Paesani's research team is international and diverse, encompassing many PhD and postdoctoral students from all over the world (USA, Mexico, India, China, Taiwan, South Korea), who are covering a wide array of topics. This gave me the opportunity to discuss other topics both within and outside of the scope of the research, as well as to learn new simulation methods such as meta-dynamics, which will help me advance in my future work. The conversations were always very cordial and direct, very similar to what I am familiar with and appreciate from Bonn. We also did a lot of things together in our free time, such as giving surfing a go or eating Korean BBQ or burritos together.

I used the university’s portal to look for a flat-share with other students and researchers. As a result, I spent three months as another researcher's subtenant. I had my own room, we shared the bathroom and had a communal living space with a kitchen. There was also a communal hot tub shared with other flats. Apart from that, the stay was unfortunately too brief to make other contacts beyond the university.

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Yosemite Panorama

The university does also offer a wide range of leisure activities. For example, a gym pass, access to swimming pools, fitness studios and other facilities such as a boul-dering hall costs around $20 a month. I was a frequent user of the swimming pool and the fitness studio on the campus. I also did my utmost to see as much of the USA as possible during my three-month stay. The national parks in particular are exceptionally impressive and beautiful. I got an opportunity to visit the Grand Canyon, Yosemite and Sequoia National Park.

From a cultural perspective, what really struck me was the friendly, open interaction between people. It was normal whilst shopping for cashier and customer to ask each other how they were doing, and standard practice when getting off a bus to thank the driver. I also found California to be very clean and tidy.

One minor culture shock, though, was how reliant on cars they are. Admittedly, there were a few buses and even a public light rail trolley system in San Diego, but it is in no way comparable to what people are used to in Germany and Europe. Which often makes it pretty much impossible to get from A to B by public transport, meaning you have to get a taxi/Uber. And so I rented a car for my trip to the national parks. One thing that I definitely underestimated prior to my stay was the sheer size of the USA. The distances between cities and even within cities are sometimes vast.

Overall, I regard the stay as a resounding success. I developed as an academic by learning plenty of new methods and getting to know plenty of new colleagues, with whom I will be staying in touch on a professional and personal basis. Moreover, I had some great cultural experiences and got a chance to improve my English. The stay was made possible by the KSB Stiftung Scholarship from the DAAD-Stiftung, for which I am extremely grateful.

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Since receiving funding from the DAAD-Stiftung, Mr. Dick has made considerable progress, as he kindly reported to us at the beginning of 2026: