NAMDIA · NonAdiabatic Molecular Dynamics of organic Intermediates in Atmospheric chemistry

NonAdiabatic Molecular Dynamics of organic Intermediates in Atmospheric chemistry

Our atmosphere is a seemingly tranquil mixture of inert gases like nitrogen. However, it actually behaves more like a massive chemical reactor, as the small portion of carbon-based molecules contained in our atmosphere can react and form new molecules in an astonishingly complex network of chemical reactions. Atmospheric chemists have developed models of these chemical networks, a tool that would help humankind predict the future composition of our atmosphere. Development of these tools is beyond a pure scientific curiosity, as human activities are changing the chemical composition of our atmosphere, impacting both climate and air quality. Because the elementary mechanistic details of volatile organic compound (VOC) – a family of carbon-based molecules – oxidation are often beyond the reach of experiment, molecular studies based on theoretical and computational chemistry are increasingly used to construct chemical models. A surprising observation, though, is that these models do not always adequately account for reactions of VOCs with sunlight. As a matter of fact, atmospheric molecules can sometimes absorb sunlight energy, bringing them into an 'excited state' that can trigger new families of 'photochemical reactions', often exotic in comparison to the normal chemistry of such molecules. This project proposed to use state-of-the-art techniques in theoretical chemistry to start answering the question: "What is the importance of photochemistry in the reaction mechanisms of atmospheric VOC intermediates?" The tools developed during this project would help theoretical chemists and atmospheric modelers to calculate how likely a VOC will absorb light and what would be the outcome of a photochemical reaction, providing insight into how excited-state dynamics impact atmospheric chemistry on global and regional scales. This project confirmed the need for theoretical photochemistry to support atmospheric chemists. By focusing on critical atmospheric molecules and by collaborating with experimentalist groups, our work led to the creation of new tools for theoretical photochemistry of VOCs and triggered at least four new research themes. Importantly, these themes need further development in the future, as improving the accuracy of atmospheric models and our fundamental understanding is paramount to solve an urgent societal problem with significant health and economic impacts. The fundamental insight provided by NAMDIA will improve the accuracy of VOC oxidation mechanisms and atmospheric models, ultimately aiding societal efforts to develop strategies that mitigate the impacts of non-CO2 species on climate change.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз