Clusters and Nanoparticles

Clusters are small agglomerates of atoms and molecules, and small meaning really minuscule pieces of matter - they consist of few to some thousands of units and have diameters in nanometer scale (0.000000001 m). The name “nanoparticle” is often used when speaking of bigger clusters with diameters from couple of nanometers to several hundreds of nanometers, but the distinction between a cluster and a nanoparticle is not well-defined.

Our speciality in NANOMO is studies of clusters and nanoparticles in the gas-phase: we create beams of free-flying clusters and nanoparticles, and we probe them by X-rays, which cause ionisations and fragmentations in them. Using electron and ion spectroscopies the charged fragments can be analysed and information on e.g. electronic and geometrical structure of clusters and nanoparticles is obtained.

Why do we want to study these systems in gas phase? The answer is two-fold. Firstly, we want to keep it simple - our goal is to study the “pure” isolated clusters and nanoparticles and thus we don’t want them to interact with each other or with substrates. Secondly, gas phase is the natural environment for many clusters and nanoparticles. Every day we are exposed to millions of gas-phase clusters and nanoparticles emitted from natural sources like trees and seas, but also from anthropogenic sources like exhaust emissions from factories and traffic. These kind of clusters and nanoparticles are often very difficult to study otherwise than in gas-phase without changing their properties drastically.

With our experimental techniques, we can obtain information of the elemental composition, structure and electronic properties of the clusters and nanoparticles. This information is essential for many other fields working with nanomatter: we can provide important insight for molecular level behaviour of e.g. clusters of atmospheric relevance (e.g. effects on climate via atmospheric chemistry) or nanoparticles of technological importance (e.g. catalysis properties, reactivity).

Nanoparticles have also promising applications in medical sciences. One of our newest research topics is to shed light to the relevant physical processes behind the proposed enhanced radiation damage in the presence of nanoparticles in radiation therapy.

But simple is not always easy. Special instrumentation is needed to create cluster and nanoparticle beams and to bring them to the interaction region with X-rays under high vacuum conditions. You can read more about this instrumentation here: http://www.oulu.fi/physics/node/9135. As can be easily imagined, gas-phase clusters and nanoparticles are very, very dilute samples, and in order to have a measurable signal, we need very bright light sources, as synchrotrons and free electron lasers. 

Synchrotron radiation based spectroscopies - Ambassadors of synchrotron light

At NANOMO, we use extremely bright light sources, synchrotrons, in our research. Synchrotron radiation light sources are particle accelerators especially optimised to produce electromagnetic radiation with many different properties  tailored for many different research fields: physics, biology, chemistry, materials science, cultural heritage, medical science… NANOMO researchers have been working at synchrotron facilities around the world from USA to Japan. Our nearest synchrotron radiation facility is in Lund, Sweden: the MAX IV laboratory (https://www.maxiv.lu.se). Professor Marko Huttula is the national coordinator of synchrotron radiation research at MAX IV and NANOMO is strongly involved to Finnish-Estonian beamline FinEstBeams (https://www.maxiv.lu.se/accelerators-beamlines/beamlines/finestbeams/), which will offer us extreme ultra-violet (EUV) and soft X-ray radiation for studies of gas and condensed phase matter. Bright, tuneable light produced by synchrotrons is vital for our own core research, but we want also to spread the word about the possibilities of these “ultimate microscopes” for researchers whose research might benefit from the synchrotron-based techniques. As ambassadors of synchrotron light, we are happy to be able contribute to multidisciplinary research projects from biology to applied materials science. 

 

Last updated: 19.1.2017