Atmospheric photochemistry at the edge – Following the production of volatile organic compounds at the air water interface with sum frequency generation spectroscopy
Oceanography
Final Report Abstract
Volatile organic compounds (VOCs) are involved in the formation of secondary organic aerosols. Due to the immense diversity of sources and reaction pathways of VOCs and their precursors, secondary organic aerosols remain a barely understood part of the Earth’s climate system. Understanding of global climate and improving computational climate models require a better understanding of the biogeochemical connection between the atmosphere and the ocean. Hence a better understanding of the formation of secondary organic aerosols and involved chemical reactions is crucial. Sum Frequency Generation spectroscopy (SFG) a surface specific vibrational spectroscopy can help getting a better understanding of the chemical reactions involved in the formation. This method provides surface specificity and possibly specificity towards certain reactions if a single vibrational mode could be attributed to the occurrence of a new chemical species. Furthermore, SFG can follow reactions with a time resolution down to a few picoseconds. Preliminary data showed a promising distinct vibrational mode at 1850 cm^-1 that appeared after UV irradiation of a nonanoic acid monolayer. Unfortunately, no attempt to reproduce this preliminary data or to find other distinct peaks that could be attributed exclusively to reactions induced by UV irradiation was successful. So that we decided to terminate the project.
