Articles | Volume 3, issue 1
https://doi.org/10.5194/ar-3-175-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/ar-3-175-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The impact of unimolecular reactions on acyl peroxy radical initiated isoprene oxidation
Ida Karppinen
Department of Chemistry, University of Helsinki, Helsinki, 00014, Finland
Dominika Pasik
Department of Chemistry, University of Helsinki, Helsinki, 00014, Finland
Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, 00014, Finland
Emelda Ahongshangbam
Department of Chemistry, University of Helsinki, Helsinki, 00014, Finland
Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, 00014, Finland
Department of Chemistry, University of Helsinki, Helsinki, 00014, Finland
Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, 00014, Finland
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Dominika Pasik, Thomas Golin Almeida, Emelda Ahongshangbam, Siddharth Iyer, and Nanna Myllys
EGUsphere, https://doi.org/10.5194/egusphere-2024-3464, https://doi.org/10.5194/egusphere-2024-3464, 2024
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We used quantum chemistry methods to investigate the oxidation mechanisms of acyl peroxy radicals (APRs) with various monoterpenes. Our findings reveal unique oxidation pathways for different monoterpenes, leading to either chain-terminating products or highly reactive intermediates that can contribute to particle formation in the atmosphere. This research highlights APRs as potentially significant but underexplored atmospheric oxidants, which may influence future approaches to modeling climate.
Dina Alfaouri, Monica Passananti, Tommaso Zanca, Lauri Ahonen, Juha Kangasluoma, Jakub Kubečka, Nanna Myllys, and Hanna Vehkamäki
Atmos. Meas. Tech., 15, 11–19, https://doi.org/10.5194/amt-15-11-2022, https://doi.org/10.5194/amt-15-11-2022, 2022
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To study what is happening in the atmosphere, it is important to be able to measure the molecules and clusters present in it. In our work, we studied an artifact that happens inside a mass spectrometer, in particular the fragmentation of clusters. We were able to quantify the fragmentation and retrieve the correct concentration and composition of the clusters using our dual (experimental and theoretical) approach.
Sabrina Chee, Kelley Barsanti, James N. Smith, and Nanna Myllys
Atmos. Chem. Phys., 21, 11637–11654, https://doi.org/10.5194/acp-21-11637-2021, https://doi.org/10.5194/acp-21-11637-2021, 2021
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We explored molecular properties affecting atmospheric particle formation efficiency and derived a parameterization between particle formation rate and heterodimer concentration, which showed good agreement to previously reported experimental data. Considering the simplicity of calculating heterodimer concentration, this approach has potential to improve estimates of global cloud condensation nuclei in models that are limited by the computational expense of calculating particle formation rate.
Nanna Myllys, Jakub Kubečka, Vitus Besel, Dina Alfaouri, Tinja Olenius, James Norman Smith, and Monica Passananti
Atmos. Chem. Phys., 19, 9753–9768, https://doi.org/10.5194/acp-19-9753-2019, https://doi.org/10.5194/acp-19-9753-2019, 2019
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In atmospheric sulfuric-acid-driven particle formation, bases are able to stabilize the initial molecular clusters and thus enhance particle formation. We have investigated the enhancing potential of different bases in atmospheric particle formation. We show that strong bases with low abundance are likely to dominate electrically neutral particle formation, whereas weak bases with high abundance have a larger role in ion-mediated particle formation.
Ulrich K. Krieger, Franziska Siegrist, Claudia Marcolli, Eva U. Emanuelsson, Freya M. Gøbel, Merete Bilde, Aleksandra Marsh, Jonathan P. Reid, Andrew J. Huisman, Ilona Riipinen, Noora Hyttinen, Nanna Myllys, Theo Kurtén, Thomas Bannan, Carl J. Percival, and David Topping
Atmos. Meas. Tech., 11, 49–63, https://doi.org/10.5194/amt-11-49-2018, https://doi.org/10.5194/amt-11-49-2018, 2018
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Vapor pressures of low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique, which is generally reported to be smaller than a factor of 2. We determined saturation vapor pressures for the homologous series of polyethylene glycols ranging in vapor pressure at 298 K from 1E−7 Pa to 5E−2 Pa as a reference set.
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Fundamental Aerosol Research (FAR)
Uptake of organic vapours and nitric acid on atmospheric freshly nucleated particles
Base synergy in freshly nucleated particles
Particle deliquescence in a turbulent humidity field
Cluster-to-particle transition in atmospheric nanoclusters
Investigation of soot precursor molecules during inception by acetylene pyrolysis using reactive molecular dynamics
Vertical concentrations gradients and transport of airborne microplastics in wind tunnel experiments
A cluster-of-functional-groups approach for studying organic enhanced atmospheric cluster formation
Photocatalytic chloride-to-chlorine conversion by ionic iron in aqueous aerosols: a combined experimental, quantum chemical, and chemical equilibrium model study
Yosef Knattrup and Jonas Elm
Aerosol Research, 3, 125–137, https://doi.org/10.5194/ar-3-125-2025, https://doi.org/10.5194/ar-3-125-2025, 2025
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Using quantum chemical methods, we studied the uptake of first-generation oxidation products onto freshly nucleated particles (FNPs). We find that pinic acid can condense on these small FNPs at realistic atmospheric conditions, thereby contributing to early particle growth. The mechanism involves two pinic acid molecules interacting with each other, showing that direct organic–organic interactions during co-condensation onto the particle contribute to the growth.
Galib Hasan, Haide Wu, Yosef Knattrup, and Jonas Elm
Aerosol Research, 3, 101–111, https://doi.org/10.5194/ar-3-101-2025, https://doi.org/10.5194/ar-3-101-2025, 2025
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Aerosol formation is an important process for our global climate. However, there are high uncertainties associated with the formation of new aerosol particles. We present quantum chemical calculations of large atmospheric molecular clusters composed of sulfuric acid (SA), ammonia (AM), and dimethylamine (DMA). We find that mixed SA–AM–DMA systems cluster more efficiently for freshly nucleated particles compared to pure SA–AM and SA–DMA systems.
Dennis Niedermeier, Rasmus Hoffmann, Silvio Schmalfuss, Wiebke Frey, Fabian Senf, Olaf Hellmuth, Mira Pöhlker, and Frank Stratmann
Aerosol Research Discuss., https://doi.org/10.5194/ar-2024-41, https://doi.org/10.5194/ar-2024-41, 2025
Revised manuscript accepted for AR
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This study examines the deliquescence behavior of NaCl particles in a turbulent humidity field using the wind tunnel LACIS-T. The results show turbulent relative humidity (RH) fluctuations affect the number of deliquesced particles, depending on mean RH, strength of humidity fluctuations, and particle residence time. It turns out that, in addition to the mean RH, it is essential to consider humidity fluctuations and particle history when determining the phase state of the deliquescent particles.
Haide Wu, Yosef Knattrup, Andreas Buchgraitz Jensen, and Jonas Elm
Aerosol Research, 2, 303–314, https://doi.org/10.5194/ar-2-303-2024, https://doi.org/10.5194/ar-2-303-2024, 2024
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The exact point at which a given assembly of molecules represents an atmospheric molecular cluster or a particle remains ambiguous. Using quantum chemical methods, here we explore a cluster-to-particle transition point. Based on our results, we deduce a property-based criterion for defining freshly nucleated particles (FNPs) that act as a boundary between discrete cluster configurations and bulk particles.
Anindya Ganguly, Khaled Mosharraf Mukut, Somesh Roy, Georgios Kelesidis, and Eirini Goudeli
Aerosol Research Discuss., https://doi.org/10.5194/ar-2024-34, https://doi.org/10.5194/ar-2024-34, 2024
Revised manuscript accepted for AR
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The study explores the formation of small soot clusters by precursor molecules at high temperature. Higher temperature speeds up the decomposition of gas molecules, accelerating the formation of cyclic structures decorated by aliphatic chains. This research offers new insights into the early steps of soot formation, which could help develop more informed kinetic models for pyrolysis and combustion processes.
Eike Maximilian Esders, Christoph Georgi, Wolfgang Babel, Andreas Held, and Christoph Karl Thomas
Aerosol Research, 2, 235–243, https://doi.org/10.5194/ar-2-235-2024, https://doi.org/10.5194/ar-2-235-2024, 2024
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Our study explores how tiny plastic particles, known as microplastics (MPs), move through the air. We focus on their journey in a wind tunnel to mimic atmospheric transport. Depending on the air speed and the height of their release, they move downwards or upwards. These results suggest that MPs behave like mineral particles and that we can expect MPs to accumulate where natural dust also accumulates in the environment, offering insights for predicting the spread and impacts of MPs.
Astrid Nørskov Pedersen, Yosef Knattrup, and Jonas Elm
Aerosol Research, 2, 123–134, https://doi.org/10.5194/ar-2-123-2024, https://doi.org/10.5194/ar-2-123-2024, 2024
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Aerosol formation is an important process for our global climate. While inorganic species have been shown to be important for aerosol formation, there remains a large gap in our knowledge about the exact involvement of organics. We present a new quantum chemical procedure for screening relevant organics that for the first time allows us to obtain direct molecular-level insight into the organics involved in aerosol formation.
Marie K. Mikkelsen, Jesper B. Liisberg, Maarten M. J. W. van Herpen, Kurt V. Mikkelsen, and Matthew S. Johnson
Aerosol Research, 2, 31–47, https://doi.org/10.5194/ar-2-31-2024, https://doi.org/10.5194/ar-2-31-2024, 2024
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We analyze the mechanism whereby sunlight and iron catalyze the production of chlorine from chloride in sea spray aerosol. This process occurs naturally over the North Atlantic and is the single most important source of chlorine. We investigate the mechanism using quantum chemistry, laboratory experiments, and aqueous chemistry modelling. The process will change depending on competing ions, light distribution, acidity, and chloride concentration.
Cited articles
Atkinson, R. and Arey, J.: Atmospheric degradation of volatile organic compounds, Chem. Rev., 103, 4605–4638, 2003. a
Atkinson, R., Baulch, D., Cox, R., Hampson Jr., R., Kerr, J., Rossi, M., and Troe, J.: Evaluated kinetic, photochemical and heterogeneous data for atmospheric chemistry: Supplement V. IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry, J. Phys. Chem. Ref. Data, 26, 521–1011, 1997. a, b
Bannwarth, C., Ehlert, S., and Grimme, S.: GFN2-xTB—An accurate and broadly parametrized self-consistent tight-binding quantum chemical method with multipole electrostatics and density-dependent dispersion contributions, J. Chem. Theory Comput., 15, 1652–1671, 2019. a
Calvert, J., Mellouki, A., Orlando, J., Pilling, M., and Wallington, T.: Mechanisms of Atmospheric Oxidation of the Oxygenates, Oxford University Press USA, ISBN 9780199767076, 2011. a
Chai, J.-D. and Head-Gordon, M.: Long-range corrected hybrid density functionals with damped atom–atom dispersion corrections, Phys. Chem. Chem. Phys., 10, 6615–6620, 2008a. a
Chai, J.-D. and Head-Gordon, M.: Systematic optimization of long-range corrected hybrid density functionals, J. Chem. Phys., 128, 8, https://doi.org/10.1063/1.2834918, 2008b. a
Clark, T., Chandrasekhar, J., Spitznagel, G. W., and Schleyer, P. V. R.: Efficient diffuse function-augmented basis sets for anion calculations. III. The 3-21+ G basis set for first-row elements, Li–F, J. Comput. Chem., 4, 294–301, 1983. a
Crounse, J. D., Nielsen, L. B., Jørgensen, S., Kjaergaard, H. G., and Wennberg, P. O.: Autoxidation of organic compounds in the atmosphere, J. Phys. Chem. Lett., 4, 3513–3520, 2013. a
Demore, W., Sander, S., Golden, D., Hampson, R., Kurylo, M., Howard, C., Ravishankara, A., Kolb, C., and Molina, M.: Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling, JPL Publication, 90, 196 pp., https://ntrs.nasa.gov/api/citations/19880014628/downloads/19880014628.pdf (last access: 11 November 2024), 1997. a
Dillon, T. J., Dulitz, K., Groß, C. B. M., and Crowley, J. N.: Temperature-dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, alpha-pinene and delta-3-carene, Atmos. Chem. Phys., 17, 15137–15150, https://doi.org/10.5194/acp-17-15137-2017, 2017. a
Dunning Jr., T. H.: Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen, J. Chem. Phys., 90, 1007–1023, 1989. a
Eckart, C.: The penetration of a potential barrier by electrons, Phys. Rev., 35, 1303, https://doi.org/10.1103/PhysRev.35.1303, 1930. a
El-Agamey, A. and McGarvey, D. J.: Acyl/aroylperoxyl radicals: a comparative study of the reactivity of peroxyl radicals resulting from the α-cleavage of ketones, Phys. Chem. Chem. Phys., 4, 1611–1617, 2002. a
Gu, C., Wang, S., Zhu, J., Wu, S., Duan, Y., Gao, S., and Zhou, B.: Investigation on the urban ambient isoprene and its oxidation processes, Atmos. Environ., 270, 118870, https://doi.org/10.1016/j.atmosenv.2021.118870, 2022. a
Hehre, W. J., Ditchfield, R., and Pople, J. A.: Self—consistent molecular orbital methods. XII. Further extensions of Gaussian—type basis sets for use in molecular orbital studies of organic molecules, J. Chem. Phys., 56, 2257–2261, 1972. a
Jenkin, M. E., Boyd, A. A., and Lesclaux, R.: Peroxy radical kinetics resulting from the OH-initiated oxidation of 1, 3-butadiene, 2, 3-dimethyl-1, 3-butadiene and isoprene, J. Atmos. Chem., 29, 267–298, 1998. a
Jenkin, M. E., Valorso, R., Aumont, B., and Rickard, A. R.: Estimation of rate coefficients and branching ratios for reactions of organic peroxy radicals for use in automated mechanism construction, Atmos. Chem. Phys., 19, 7691–7717, https://doi.org/10.5194/acp-19-7691-2019, 2019. a
Johnston, H. S. and Heicklen, J.: Tunnelling corrections for unsymmetrical Eckart potential energy barriers, J. Phys. Chem., 66, 532–533, 1962. a
Karppinen, I.: The impact of unimolecular reactions on acyl peroxy radical initiated isoprene oxidation, In Aerosol Research, Zenodo [data set], https://doi.org/10.5281/zenodo.15112994, 2025. a
Kendall, R. A., Dunning, T. H., and Harrison, R. J.: Electron affinities of the first-row atoms revisited. Systematic basis sets and wave functions, J. Chem. Phys., 96, 6796–6806, 1992. a
Kleindienst, T. E., Harris, G. W., and Pitts, J. N.: Rates and temperature dependences of the reaction of hydroxyl radical with isoprene, its oxidation products, and selected terpenes, Environ. Sci. Technol., 16, 844–846, 1982. a
Kubečka, J., Besel, V., Kurtén, T., Myllys, N., and Vehkamaki, H.: Configurational sampling of noncovalent (atmospheric) molecular clusters: sulfuric acid and guanidine, J. Phys. Chem. A, 123, 6022–6033, 2019. a
Lee, S.-H., Gordon, H., Yu, H., Lehtipalo, K., Haley, R., Li, Y., and Zhang, R.: New particle formation in the atmosphere: From molecular clusters to global climate, J. Geophys. Res.-Atmos., 124, 7098–7146, 2019. a
McMahon, R. J.: Chemical reactions involving quantum tunneling, Science, 299, 833–834, 2003. a
Meana-Pañeda, R., Truhlar, D. G., and Fernández-Ramos, A.: High-level direct-dynamics variational transition state theory calculations including multidimensional tunneling of the thermal rate constants, branching ratios, and kinetic isotope effects of the hydrogen abstraction reactions from methanol by atomic hydrogen, J. Chem. Phys., 134, 9, https://doi.org/10.1063/1.3555763, 2011. a
Møller, K. H., Otkjær, R. V., Chen, J., and Kjaergaard, H. G.: Double bonds are key to fast unimolecular reactivity in first-generation monoterpene hydroxy peroxy radicals, J. Phys. Chem. A, 124, 2885–2896, 2020. a
Neese, F.: The ORCA program system, Wiley Interdisciplinary Reviews: Computational Molecular Science, 2, 73–78, 2012. a
Nozière, B. and Vereecken, L.: H-shift and cyclization reactions in unsaturated alkylperoxy radicals near room temperature: propagating or terminating autoxidation?, Phys. Chem. Chem. Phys., 26, 25373–25384, 2024. a
Nozière, B., Durif, O., Dubus, E., Kylington, S., Emmer, Å., Fache, F., Piel, F., and Wisthaler, A.: The reaction of organic peroxy radicals with unsaturated compounds controlled by a non-epoxide pathway under atmospheric conditions, Phys. Chem. Chem. Phys., 25, 7772–7782, 2023. a
Otkjær, R. V., Jakobsen, H. H., Tram, C. M., and Kjaergaard, H. G.: Calculated hydrogen shift rate constants in substituted alkyl peroxy radicals, J. Phys. Chem. A, 122, 8665–8673, 2018. a
Pasik, D., Frandsen, B. N., Meder, M., Iyer, S., Kurtén, T., and Myllys, N.: Gas-Phase Oxidation of Atmospherically Relevant Unsaturated Hydrocarbons by Acyl Peroxy Radicals, J. Am. Chem. Soc., 146, 13427–13437, 2024a. a
Pracht, P., Bohle, F., and Grimme, S.: Automated exploration of the low-energy chemical space with fast quantum chemical methods, Phys. Chem. Chem. Phys., 22, 7169–7192, 2020. a
Riplinger, C. and Neese, F.: An efficient and near linear scaling pair natural orbital based local coupled cluster method, J. Chem. Phys., 138, 3, https://doi.org/10.1063/1.4773581, 2013. a
Riplinger, C., Sandhoefer, B., Hansen, A., and Neese, F.: Natural triple excitations in local coupled cluster calculations with pair natural orbitals, J. Chem. Phys., 139, 13, https://doi.org/10.1063/1.4821834, 2013. a
Sandhiya, L. and Senthilkumar, K.: Unimolecular decomposition of acetyl peroxy radical: a potential source of tropospheric ketene, Phys. Chem. Chem. Phys., 22, 26819–26827, 2020. a
Stevens, P. S., Seymour, E., and Li, Z.: Theoretical and experimental studies of the reaction of OH with isoprene, J. Phys. Chem. A, 104, 5989–5997, 2000. a
Vereecken, L. and Nozière, B.: H migration in peroxy radicals under atmospheric conditions, Atmos. Chem. Phys., 20, 7429–7458, https://doi.org/10.5194/acp-20-7429-2020, 2020. a, b, c
Vereecken, L. and Peeters, J.: The 1, 5-H-shift in 1-butoxy: A case study in the rigorous implementation of transition state theory for a multirotamer system, J. Chem. Phys., 119, 5159–5170, 2003. a
Vereecken, L. and Peeters, J.: Nontraditional (per) oxy ring-closure paths in the atmospheric oxidation of isoprene and monoterpenes, J. Phys. Chem. A, 108, 5197–5204, 2004. a
Viegas, L. P.: Exploring the reactivity of hydrofluoropolyethers toward OH through a cost-effective protocol for calculating multiconformer transition state theory rate constants, J. Phys. Chem. A, 122, 9721–9732, 2018. a
Viegas, L. P.: Simplified protocol for the calculation of multiconformer transition state theory rate constants applied to tropospheric OH-initiated oxidation reactions, J. Phys. Chem. A, 125, 4499–4512, 2021. a
Villenave, E., Lesclaux, R., Seefeld, S., and Stockwell, W. R.: Kinetics and atmospheric implications of peroxy radical cross reactions involving the CH3C (O) O2 radical, J. Geophys. Res.-Atmos., 103, 25273–25285, 1998. a
Wennberg, P. O., Bates, K. H., Crounse, J. D., Dodson, L. G., McVay, R. C., Mertens, L. A., Nguyen, T. B., Praske, E., Schwantes, R. H., Smarte, M. D., St Clair, J. M., Teng, A. P., Zhang, X., and Seinfeld, J. H.: Gas-phase reactions of isoprene and its major oxidation products, Chem. Rev., 118, 3337–3390, 2018. a
Xu, L., Møller, K. H., Crounse, J. D., Otkjær, R. V., Kjaergaard, H. G., and Wennberg, P. O.: Unimolecular reactions of peroxy radicals formed in the oxidation of α-pinene and β-pinene by hydroxyl radicals, J. Phys. Chem. A, 123, 1661–1674, 2019. a
Zhang, F. and Dibble, T. S.: Impact of tunneling on hydrogen-migration of the n-propylperoxy radical, Phys. Chem. Chem. Phys., 13, 17969–17977, 2011. a
Zhao, Y. and Truhlar, D. G.: The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals, Theor. Chem. Account., 120, 215–241, 2008. a
Short summary
Acyl peroxy radicals can act as atmospheric oxidants of unsaturated hydrocarbons if their 1) unimolecular reactions are slow and 2) bimolecular accretion reactions are fast. Using theoretical tools, we show which acyl peroxy radicals should be considered oxidants in the atmosphere.
Acyl peroxy radicals can act as atmospheric oxidants of unsaturated hydrocarbons if their 1)...
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