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PhD candidate Thijs Stuyver defended his thesis on the electrical conduction of molecules in front of a panel which included Nobel prize-winning chemist Roald Hoffmann, who had flown in especially for the occasion. The two cemented their growing friendship during a three-month study period at Cornell University. Hoffmann grew up in a Jewish family during World War II and survived the Holocaust by hiding in a local schoolhouse. A published playwright and poet in addition to his scientific writing, Hoffmann’s lifelong mission is to understand the world and communicate what he discovers in a way that connects with people.


PhD candidates at the VUB are accustomed to defending their theses in front of eminent academics. But it’s not every day that a Nobel laureate flies in from the United States to sit on the jury.


On Wednesday 31st May, PhD candidate Thijs Stuyver, 26, had the honour of defending his doctorate in front of the 80-year-old theoretical chemist Roald Hoffmann, Frank H. T. Rhodes Professor Emeritus at Cornell University. Hoffmann won the Nobel Prize for Chemistry in 1981 for his investigation into the mechanisms of chemical reactions, along with Japan’s Fukui Kenichi.


Stuyver’s PhD explores how molecules can serve as electrical conductors. The technology is especially applicable in computing, where researchers are constantly trying to reduce the size of components.


In the 1960s, Intel co-founder Gordon Moore predicted that the number of transistors per silicon chip, and thus the performance of computer processors, would double roughly every two years. His projection held until the mid 2000s, when improvements in performance started to tail off.


Up till now, transistors have been printed onto silicon plates using lasers. “The original idea of molecular electronics is to turn this around, working from the bottom up,” says Stuyver.


“You take molecules and make electrical components out of these. In my research group at the VUB, we try and see how the structure of a molecule influences that molecule’s ability to transport electrical current. From this information, we propose new experiments for researchers elsewhere to carry out”.


Stuyver’s research also has potential applications in medicine, since charge transfer plays an important role in biological processes.


A natural selection

Professor Hoffmann first contacted Stuyver after coming across a paper he had worked on about a ‘selection rule’ for molecular conduction. He says ready access to international scientific research made the exchange possible.


“We had mutual interests, but it’s interesting that those came up through the literature,” says Hoffmann.


“The reason this works is that there is an open and diverse literature that is available to everyone. It used to be physical journals, but now we see these papers on the web.”


The email correspondence soon turned into face-to-face contact when Stuyver asked Hoffmann if he could work with him at Cornell University in the US for a few months, and Hoffmann accepted.


During Stuyver’s three months at Cornell, which was funded by the FWO (Research Foundation – Flanders), Hoffmann became a mentor and the research ties between Cornell and the VUB deepened. For Hoffmann, it was therefore “only natural that I would be on the jury” for Stuyver’s PhD defence.


Whilst Hoffmann appreciates the many potential applications of Stuyver’s research on molecular electronics, he is clear on the importance of getting the theory right first. “I stand for basic knowledge and fundamental research in chemistry,” he says.


“It’s not that I don’t care about helping humanity. But you cannot do that by just taking any chemical off the shelf and trying it. It’s a planned enterprise which depends on understanding. My co-workers and I are involved in providing that basic understanding. Other people then apply that research to concrete projects.”


With his PhD now completed, Stuyver is off to the Hebrew University in Jerusalem where he will work with the renowned theoretical chemist, Professor Sason Shaik.


Hoffmann’s advice for the future? “Stay curious about things and always try to see alternative points of view. Keep asking questions about why and how things happen.”


Return to Europe

The last time Roald Hoffmann visited Brussels was forty years ago. Since then, much has changed. “Back then, you could never find a menu in English!” he recalls. “It’s now a European capital in many ways, and a very international place.”


But Europe was not always so welcoming. Born into a Jewish family in Złoczów, Poland (now Ukraine), the young Hoffmann and his mother survived the Holocaust by hiding in the attic of a local schoolhouse for 18 months. His father was murdered by the Nazis. Passing through Czechoslovakia, Austria and Germany, the family eventually emigrated to the US when Hoffmann was 11 years old.


“Did the wartime experiences as a child influence my psychology? Probably. There was certainly a feeling that this should not happen again, and that one should work towards justice and peace. To this day I’m afraid of people in uniform, even doormen outside a house.”


However, Hoffmann does not feel his early years have impacted directly on his science. “Except that, growing up as immigrant in post-war Europe, I certainly took advantage of every opportunity. Later the scientific system opened up, with relative lack of prejudice, to all ethnic groups. There were no barriers to moving ahead – so I took advantage of that.”


Hoffmann is less sanguine about the role of scientific cooperation in peacekeeping. “Scientists have a common language to talk across cultures and across nationalities,” he says. “However, in times of crisis, scientists have gotten just as nationalistic as anyone else. We saw it during the First and Second World Wars. Scientists succumb just as much to false patriotism, excesses of nationalism and self-justification as other people.”


Understanding the world

It’s not just important that scientists learn to communicate with and learn from each other. They should also seek to explain their work to those beyond the scientific community, says Hoffmann. He explains that the “neutered, third-person” language of contemporary science writing often creates a barrier between the reader and the observer.


“It became important to communicate the experience [of scientific discovery] independent of the observer. That was the purpose of third person dialogue. The result of that style, however, is that it creates a distance… People think scientists are remote people who are just smarter than they are. But they’re really not. Scientists are practical people just trying to understand the world.”


Alongside his distinguished career in chemistry, Hoffmann is also a published poet and playwright. He says his literary endeavours give him “a way to express emotional things which are difficult to get across in science”.


“I try to snake my writing into my chemistry work,” he says. “For instance, if I say the calculation of this property is not unambiguous, that it can be done in way A or way B, and that we have chosen to do it in a particular way, actually that rather innocent statement communicates something to the reader. It fights the notion in science that there is a correct and an incorrect way of doing things. If I can communicate to the reader that what I am doing is difficult, that actually gets sympathy! It elicits an emotional response.”