Microfysica van wolkvorming: het pad naar heterogene nucleatie

The process that kicks off the cloud (or dust particle) formation is the nucleation process by which gas-phase species grow to larger clusters which then grow into condensation seeds. Given the chemical richness of planetary atmospheres, we need to explore heterogeneous nucleation paths, in contrast to the classical homogeneous nucleation of TiO2, SiO and others. The research question of this project is: Which mineral hazes form in exoplanet atmospheres and how do they lead to the formation of cloud-condensation nucleii? We will begin by studying the formation of VO and YO clusters in order to become acquainted with the quantum-chemical approaches, for example DFT. Then we will map the TiO2 result for the chemically similar elements Ti, V and Y. This will be followed by the study of Al-O and Zr-O cluster formation. The derived thermodynamic data will be used to derive cluster formation rates and added to the STAND2020 kinetic chemistry code for exoplanet and brown dwarf atmospheric environments. A thorough study of cluster formation under the condition of exoplanet atmospheres is to be conducted, and comparisons to previous works, like the homogeneous approach in Boulangier et al. (2019), will be done. The cluster abundances will be studied for specific exoplanets (for example a hot Neptune, a hot gas giant and an ultra-hot Jupiter) in order to derive possible observable finger prints for cloud formation. The cluster data for VO and YO in addition to TiO2 can now be explored to derive homogeneous nucleation rates, and those for Al2O3 and Zr2O3 will be used to explore paths to describe heterogeneous nucleation.