BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:CECAM Workshop:"Theoretical and experimental advances in atmospher ic photochemistry" DTSTART;VALUE=DATE:20240326 DTSTAMP:20260407T051439Z UID:cae52401c1fa990eb04d642f5839ae28795cecd620a850bf832de5e9 CATEGORIES:Conferences - Seminars DESCRIPTION:You can apply to participate and find all the relevant informa tion (speakers\, abstracts\, program\,...) on the event website: https://w ww.cecam.org/workshop-details/1205 \n*** REGISTRATION DEADLINE *** : 20th February 2024\n\nDescription\nAt first glance\, the Earth’s atmosphere appears to be mainly composed of simple\, inert gases like O2\, N2\, or th e infamous CO2. However\, the reality is somewhat different\, and our atmo sphere behaves more like a massive chemical reactor due to the presence of reactive molecules like CH4\, halocarbons\, O3\, N2O\, NO\, or volatile o rganic compounds (VOCs). The degradation of biogenic and anthropogenic VOC s takes place via a highly complex network of chemical processes and is in timately connected to the concentration of OH\, ozone\, and secondary orga nic aerosol (SOA) precursors in the troposphere. The result of this is VOC s are strong contributors to both global warming and air pollution\, and a great deal of effort has been devoted to understanding and predicting the ir atmospheric concentrations using detailed chemical models. As environme ntal policy decisions are driven by such atmospheric models\, it is essent ial they accurately reflect the different chemical reactions in the atmosp here.\nHistorically\, these chemical mechanisms have mostly neglected reac tions involving the interaction of VOC intermediates with sunlight\, and t he resulting photochemical reactions. Hence\, a complete family of chemica l reactions is missing in current atmospheric models\, and the influence o f these reactions on the composition of our atmosphere is largely unknown\ , partly as photochemical experiments on (transient) VOCs are highly compl ex to realize.\nHow can theoretical and computational chemistry help? Simu lating the photochemistry of a molecule requires the inclusion of nonadiab atic effects\, i.e.\, the coupling between electronic states and nuclear m otion\, which is not straightforward as it challenges several approximatio ns commonly used in theoretical chemistry. For example\, nonadiabatic effe cts lead to a breakdown of the Born-Oppenheimer approximation\, classical approximations for the nuclear degrees of freedom may be inadequate\, and out-of-equilibrium processes can challenge established reaction rate theor ies.\nWhile numerous methods have been devised to tackle these issues – e.g.\, MCTDH\, trajectory surface hopping\, ab initio multiple spawning – their application to study the photochemistry of atmospheric molecule s faces numerous challenges. Examples are: the complexity in simulating ob servables of interest for spectroscopists and atmospheric modelers\; the c hallenging electronic structure of multichromophoric VOCs\; the types of e xcited-state dynamics created by sunlight excitation\; the long-time excit ed-state dynamics associated with VOCs\; the importance of intersystem cro ssings or collisional processes\; and the effect of an aqueous environment \, such as in atmospheric aerosols and clouds.\nOver the last decades\, at mospheric chemistry has stimulated the development of new theoretical meth ods to investigate complex ground-state chemical reactions and their mec hanisms. Such a connection between theory and experiment does not current ly exist in atmospheric photochemistry involving electronically excited s tates\, despite the importance for current atmospheric models and a strong push from the experimental side to obtain reliable data for modeling the composition of the atmosphere. With this CECAM workshop\, we wish to creat e a bridge between the worlds of computational photochemistry and atmosphe ric chemistry to bolster a synergistic discussion between these two groups aiming to (i) connect theory with experiment\, (ii) define key targets fo r theory\, and (iii) identify current theoretical challenges and their pos sible solutions. \n\nReferences\n[1] J. Beames\, F. Liu\, L. Lu\, M. Lest er\, J. Am. Chem. Soc.\, 134\, 20045-20048 (2012)\n[2] L. Vereecken\, D. Glowacki\, M. Pilling\, Chem. Rev.\, 115\, 4063-4114 (2015)\n[3] R. Gerbe r\, M. Varner\, A. Hammerich\, S. Riikonen\, G. Murdachaew\, D. Shemesh\, B. Finlayson-Pitts\, Acc. Chem. Res.\, 48\, 399-406 (2015)\n[4] M. Barbat ti\, J. Chem. Theory Comput.\, 16\, 4849-4856 (2020)\n[5] M. Ončák\, L. Šištík\, P. Slavíček\, The Journal of Chemical Physics\, 133\, 1743 03 (2010)\n[6] A. Prlj\, L. Ibele\, E. Marsili\, B. Curchod\, J. Phys. Che m. Lett.\, 11\, 5418-5425 (2020)\n[7] M. McGillen\, B. Curchod\, R. 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Chem. Phys.\, 23\, 25597-25611 (202 1)\n  LOCATION:BCH 2103 https://plan.epfl.ch/?room==BCH%202103 STATUS:CONFIRMED END:VEVENT END:VCALENDAR