At UC Berkeley they are leader researchers in Solvation Science and founders of CALSOLV, the partner institute of RESOLV in California. In everyday life they are married. Teresa and Martin Head-Gordon collaborate with RESOLV since its inception and visited RUB many times already. We interviewed them.
What is your research about?
Teresa: I have a long standing interest in bulk water, both theoretically and experimentally. My group delivered the first accurate radial distribution function of water. After that we looked at the interplay of proteins and water, also using new experimental approaches like quasi-elastic neutron scattering, to look at dynamics in addition to structure. We now aim for a more accurate theoretical description of solvation and to deal with greater complexity than just bulk water.
Martin: I have a background in theoretical and computational chemistry applied on gas phase. Over the past decade I’ve contributed to the theory of the physical origin of the molecular interactions, also in liquid phase. I am currently developing a general framework to analyse any kind of intermolecular interaction.
What fascinates you about Solvation Science?
Teresa: Water. Solvation can be more than water, but water really is a unique liquid, it doesn’t behave like other liquids, it’s everywhere, but scientifically speaking is a constant surprise. There are certain regions of the water phase diagram that are experimentally inaccessible, that’s where theory is needed to explore them. On the other hand, water is the primary solvent for life, it plays a special role: Enzymes, for example, learned how to exploit water for their benefit during their evolution.
Martin: In solvation science there’s a nice mix of fundamental physical problems – for example about what physical forces drive solvation phenomena. I am fascinated by the molecular interactions that occur between solvent and solute.
Why does your research on Solvation Science matter?
Teresa: Because we are recognising that the solvent is an active player, not only some kind of inert backdrop. Therefore it’s directly responsible for functional outcomes in biology, chemistry and geology. Solvation is an environmental effect that needs to be described explicitly. Take for example our research on designing synthetic biocatalysts that mimic natural enzymes. These synthetic biocatalysts could be useful in industry and green technology. An interesting question there is if the solvent plays an active role in optimizing function of the new molecule, as it does in the natural case.
Martin: Solvation science encompasses a range of important and practical problems. I currenty work on a project in electrocatalysis. The big challenge there is being able to reduce CO2, the most important greenhouse gas, into chemicals like ethanol or ethane. This is another case where the solvent has an important role. Forging this kind of electrocatalysts may be useful for the chemical industry as well as to mitigate climate change.
Why did you decide to constitute CalSolv?
Teresa: I have known Martina Havenith for a long time and wanted to formally collaborate with her. Other colleagues from Berkley also had individual collaborations with Bochum scientists. So when RESOLV started, its interdisciplinary approach was very inspiring. It became a natural consequence to join forces with local colleagues in Berkeley we wouldn’t normally connect to – experimentalists and theoreticians. Then an international grant for student’s exchange between RESOLV and CalSolv gave as the opportunity to formalise us both as a group and sister center to RESOLV.
With whom do you collaborate at RUB/RESOLV?
Teresa: Last year we spent more than one month at RUB. I interacted with Martina Havenith and Dominik Marx. With Martina we tested some of the synthetic biocatalysts. With Dominic we tried different types of theoretical techniques to make predictions and also tested them with Havenith.
Martin: Being mainly a theoretician, it’s important for me to seek connections with experimentalists. I have been collaborating with Stefan Huber on halogen bonding and interacting with Dominik Marx on acid dissociation in nanodroplets.
How do you value the students’ exchanges and the collaborations with RESOLV?
Teresa: They are very much important to boost the progress in solvation science, because we complement each other, in terms of resources, facilities and expertise. These collaborations led to the foundations of the joint proposal for the Research Training Group Confinement-controlled Chemistry, which was recently granted by the DFG.
Let’s go back to hard science. Are your theories tested experimentally?
Martin: There’s always a partnership between theory and experiment. Without the modelling the experiment gives only the final products, whereas the modelling allows us to gain an insight into the intermediates along the reaction pathways. On the other hand, the modelling without the experiment doesn’t allow us to be confident about the predications, so experiments provide validation to the modelling.
Where has solvation research progressed more?
Martin: Exactly in this partnership between theory and experiment! Important computational advances over the past decades have laid the ground work for what RESOLV does today – for example the development of ab Initio dynamics as a practical tool to study condense phase reactions. Then there has been a great leap in the experiments, like THz spectroscopy, that allow us new insights on how ions and hydration shells move around, vibrate, rearrange.
Teresa: What happened in the subject of protein folding is a good example in this respect. Years ago, the time scale for folding was from milliseconds to seconds and you could only simulate for hundreds of nanoseconds. The experimentalists tried to find faster folding proteins, and got down to microseconds. Finally the simulation camp came up to simulate for longer time to get in the microsecond range – and more recently the DE Shaw group has advanced to milliseconds. That’s how experiment and theory met.
What are the next challenges in solvation science?
Teresa: The next significant frontier is to study how strongly confining structures and surfaces affect solvent behaviour and chemical reactivity. We start simulating water under confinement at the nanoscale with ab initio approaches, but to create the experimental conditions is a true enterprise: One would need to fabricate very small systems in the nanometre scale. Another challenge is to study solvation under non-equilibrium conditions.
Finally, I would be happy to translate our efforts in solvation science into solutions that have an impact on human needs. Solvation science can answer questions like “How do we create clean water through reverse osmosis? How do we avoid nutrient pollution?”.
Martin: On the computational side there is need for increased accuracy, to be fully capable to make condense phase predictions.
How is it to work as a couple in the same field?
Teresa: Sometimes we can be competitive, but we also share success. We talk shop a lot, almost 24/7!
Martin: In a way it’s great fun! We share personal life and professional life, sometimes we have to work hard to switch off work.
What are your advices to young students willing to pursue a career in science?
Teresa: Don’t turn down opportunities! Even if don’t know how to start something, because it seems too big an enterprise, take a chance! Take one step at time, then opportunity will take you into unexpected places. And while industry and commercial jobs are interesting challenges, don’t leave Academia too easily: It is the best job in the world!
Martin: Do what really excites you, what you really like the most! By doing the thing that you love it will feel like a hobby, you will be most creative and effective. Then opportunities will open up because of the excellence that you achieve.
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