Puck van Gerwen

Puck van Gerwen, a member of NCCR Catalysis who contributes to some MARVEL activities, moved around a lot as a child. As a result, she has three nationalities and speaks four languages. Puck was in Switzerland when she was 18 and thinking about university and, while she considered staying in the country, the International Baccalaureate (IB) degree that she had done in high school isn’t immediately recognized. While waiting to hear about her options, she was accepted to the University of Edinburgh in Scotland and decided to take them up on the offer. She studied chemical physics and liked it a lot, except for all the lab work, which she did “not enjoy at all”. This prompted her to move away from the lab and start a master’s in theoretical physics for materials science applications. It was difficult because her undergraduate studies hadn’t provided much of the necessary physics background, but she nonetheless really enjoyed the experience, saying it was the most she’d ever been pushed. She then chose to pursue a PhD to keep learning. After spending a year with Prof. Anatole von Lilienfeld’s group at the University of Basel, she chose to remain in Switzerland after the group moved to Austria. She is now working with Prof. Clemence Corminboeuf’s Computational Molecular Design Laboratory at EPFL. In her free time, Puck enjoys climbing, mountaineering and skiing. She has also recently started ballet and enjoys painting with acrylics when she can find the time. 

Interview by Carey Sargent, EPFL, NCCR MARVEL, February 2023

Have you always been interested in science?

I think I’m atypical in that my attachment was not necessarily to science—I was always obsessed with learning. Unlike many other people, I really liked school. Not even to see my friends or whatever, but for the fact that you got to do everything, language and science and writing. I always liked this and it’s actually something that I found difficult when I went to university. It was like “now you have to focus on this one thing.”

The range is coming back a bit more in the PhD, you need to write more, you’re not just doing maths all the time, you have more diverse things that you do during your day and I prefer this a lot. I was maybe more skilled at science, and I think I had a gift for maths, and maybe that’s why I ended up studying physical chemistry, but I liked everything.

While the IB program is a bit more flexible than other systems, you still need to take three subjects to a higher level and three subjects to a lower level. Normally the choices that you make start to reflect what you’re going to study. So you’re not encouraged to take, say, French and Maths and Art. You’re supposed to sort of tailor it in the direction you want to go. The main subject I was really attached to at school was maths and so I was trying to shape it around that. Because you have to take these two other subjects that are supposed to go together, my natural second choice was physics and then chemistry was almost an afterthought, which is funny, because I’m now a chemist.

I really liked maths but was daunted by the idea of studying it because it’s a completely  mental exercise. Even at school, if I was doing a lot of it, I’d sometimes find that my brain would hurt so I didn’t want to do that 100%. I was trying to find something that would fit, something that was still mathematical, but not 100%.

What motivates you? 

I think it is this drive for learning that has been a common factor in my whole life. My friends make fun of me because I pick up something new and then become obsessed with it. A few years ago, I got really into climbing and skiing, so mountain sports, but not just in a “oh, I’ll try it out” way. Like I go to a climbing gym once and then buy a membership and go three times a week. It’s a bit how my brain is. I try something, I like it, and become obsessed. It can be a lot of different things, but basically, it’s this drive to learn. I think the obsession comes from wanting to do it well.  

What’s the aim of your research in general?

My PhD in general is about developing machine learning models for chemical reactions. Over the last ten years or so there has been a lot of effort in molecular machine learning, which has come both from the chemistry and physics communities, but also from computer science because they realized that they can use everything that’s developed for graphs also for molecules. What I’m trying to do is taking what has been done from those developments and trying to extend it to chemical reactions, which are much more difficult because you no longer have a single molecule, you have many of them and they interact and you have conditions and solvents and so on, but we’re still doing it from a physics-based perspective so it’s still quite fundamental.   At this stage can’t necessarily use it to study real life reactions, but that’s the end goal.  

Which papers are you most proud of?

I think you always have a paper that’s your baby. My “baby paper” is Physics-based representations for machine learning properties of chemical reactions. This one was my baby because it was supposed to be the first step for this direction of my PhD and I worked on it a lot, for about a year, with a lot of effort and passion and sometimes it looked like it wasn’t going to work. There was a period where we thought that maybe we couldn’t publish it because it looked too much like something else and so it was very…emotional! I was quite proud of that one because one day, I was just like “No, we’re going to publish it now”. I just decided at some point that I needed to publish it how it was. Obviously, something can always be better, but we wrote the paper and it was actually quite nice. I was really proud of that one. I honestly felt like I gave birth to it. Everything after that got a lot easier. 

Do you think women face particular challenges in science? 

I agree with a colleague who doesn’t think it’s a science-specific problem, but I do think science is one discipline where you can see the problem. The biggest problem in my opinion is that it’s a subtle societal pressure on how women are supposed to be compared to men. This affects you already when you’re a child and the problem is that it is something that is so deep that it’s actually hard to even recognize or dislodge. When I was younger, until I finished my Bachelor’s, I would have said there’s no problem for women in science. Because it’s something so ingrained in society you almost don’t recognize it anymore. It took me until I was in my mid-20s to start seeing it.

One of the ways it manifests, at least that’s how it was for me, is that women are not encouraged to have this growth mindset where you’re allowed to fail and fail again until it works. And this is tied to a confidence problem because I think there is this pressure, and it’s a perfectionist thing as well, I think that women are much less confident about themselves and their accomplishments. The way I had it,  at school as well, was that in order to feel comfortable about making a decision, like deciding that I want to study maths or physics or whatever, I felt like I had to be the best in the class. I see this again and again, also in others, that women are much quicker to question ourselves or our accomplishments and are not encouraged to have a growth mindset.  

Men have a deeper internal confidence or belief that everything will be fine, and it is very important to fail and accept that something might not be perfect but do it anyway. I think that this is part of the problem—women don’t go for things unless they’re overqualified, they won’t publish a paper unless they think it’s perfect. You don’t study physics because you don’t think you’re good enough, you don’t publish your paper because you’re not confident enough that it’s good, you don’t ask for a raise, because you don’t think you deserve it. All these things build up, and that’s also why you see that it gets worse over the timeline—these things add up.  Then you obviously have the kids problem as well… 

Do you have any advice for younger women interested in science? 

They should not be afraid of failing, but should believe in themselves and keep trying. If it’s something you want to do, you should just believe that you’ll get there. I have a friend who I really respect because she studied maths and in the first year she failed everything but she tried again and now she’s doing a PhD in the subject and she’s really good. There’s a make-or-break point: do you continue even though you failed? I think you should keep pushing yourself to fail because that’s how you grow.