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The dimerization of glycine is the simplest oligomerization of amino acids and plays an important role in biology. Although this reaction is thermodynamically unfavorable in the aqueous phase, it has been shown to be spontaneous in the gas phase and proceeds via two different concerted reaction mechanisms known ascisandtrans. This may have profound implications in prebiotic chemistry as common atmospheric prenucleation clusters are thought to have participated in gas‐phase reactions in the early Earth's atmosphere. We hypothesize that particular arrangements of water molecules in these clusters could lead to lowering of the reaction barrier of amino acid dimerization and could lead to abiotic catalysis toward polypeptides. We test our hypothesis on a system of thecistransition state of glycine dimerization solvated by one to five water molecules using a combination of a genetic algorithm‐based configurational sampling, density functional theory geometries, and domain‐based local pair natural orbital coupled‐cluster electronic structure. First, we discuss the validity of the model chemistries used to obtain our results. Then, we show that the Gibbs free energy barrier for the concertedcismechanism can indeed be lowered by the addition of up to five water molecules, depending on the temperature.

Aerosols significantly influence atmospheric processes such as cloud nucleation, heterogeneous chemistry, and heavy‐metal transport in the troposphere. The chemical and physical complexity of atmospheric aerosols results in large uncertainties in their climate and health effects. In this article, we review recent advances in scientific understanding of aerosol processes achieved by the application of quantum chemical calculations. In particular, we emphasize recent work in two areas: new particle formation and heterogeneous processes. Details in quantum chemical methods are provided, elaborating on computational models for prenucleation, secondary organic aerosol formation, and aerosol interface phenomena. Modeling of relative humidity effects, aerosol surfaces, and chemical kinetics of reaction pathways is discussed. Because of their relevance, quantum chemical calculations and field and laboratory experiments are compared. In addition to describing the atmospheric relevance of the computational models, this article also presents future challenges in quantum chemical calculations applied to aerosols.