Erika Sundén is one of the PhD students in the Nanoparticle platform. Her project is titled "Thermodynamic stability of charged water clusters" and is aimed at getting a better understanding of the earliest stages of cloud formation. Her primary supervisor is Klavs Hansen and her secondary supervisor is Patrik Andersson.
Clouds are continually formed and dissolved in the atmosphere, but still very little is known about the process of the earliest stages of the droplet formation, where one of the reasons is that they are too small to study in their natural environment. It is believed that ions created by radiation from outside the earth as well as other substances in the atmosphere such as sulfates and ammonia play an important part in the aggregation of the water clusters, but to what extent is not yet known. This is what the project aims to find answers to. The water clusters (pure or lightly contaminated with substances relevant for the atmosphere) are produced in a supersonic expansion and studied in a vacuum chamber equipped with time-of-flight mass spectrometry. The metastable fragmentation is measured by using a reflectron and a pulsed laser.