Bridging science and industry: fundamental discoveries driven by industrial challenges 

Where do researchers in fundamental science get their inspiration from? The Ion Interactions research group of Ronnie Hoekstra investigates ion interactions with matter. Typically, they focus on interactions of light ions with molecules. However, with ARCNL being a public-private partnership with – among others – the lithography company ASML, they began to wonder ‘what happens when heavy tin ions interact with molecules?’ A relevant question since ASML uses tin to produce extreme ultraviolet (EUV) light.  Ronnie Hoekstra:

“We were thinking, where do the singly charged tin ions come from in the hydrogen buffer gas surrounding the tin-plasma-based EUV light source, which expels only multiply charged tin ions? We made similar observations in our ARCNL plasma setup where an unexpectedly high abundance of singly charged tin ions was measured.”

Combining advanced experiments at the ZERNIKELEIF ion beam facility at the University of Groningen with quantum wave packet modeling at the Universidad Autónoma de Madrid, the team demonstrated that the unexpected presence of singly charged tin ions stems from synchronous, sequential two-electron capture by triply charged tin ions. During this process, the hydrogen molecule dynamically adjusts its bond length, significantly increasing the probability of both capture events. 
This discovery not only resolves a mysterious observation but also unveils a previously unknown reaction mechanism in ion-molecule interactions. It highlights how fundamental scientific research can emerge from observation in high-tech industry and deepen our understanding of molecular dynamics. 

On March 7th, the findings were published in the journal Physical Review Letters. Read more about the fascinating response mechanism.