Search Results - "Vehkamäki, H"

Methane sulfonic acid-enhanced formation of molecular clusters of sulfuric acid and dimethyl amine by Bork, N, Elm, J, Olenius, T, Vehkamäki, H

“…Over oceans and in coastal regions, methane sulfonic acid (MSA) is present in substantial concentrations in aerosols and in the gas phase. We present an…”
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Enhancing effect of dimethylamine in sulfuric acid nucleation in the presence of water – a computational study by Loukonen, V., Kurtén, T., Ortega, I. K., Vehkamäki, H., Pádua, A. A. H., Sellegri, K., Kulmala, M.

“…We have studied the hydration of sulfuric acid – ammonia and sulfuric acid – dimethylamine clusters using quantum chemistry. We calculated the formation…”
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Atmospheric Cluster Dynamics Code: a flexible method for solution of the birth-death equations by McGrath, M. J, Olenius, T, Ortega, I. K, Loukonen, V, Paasonen, P, Kurtén, T, Kulmala, M, Vehkamäki, H

“…The Atmospheric Cluster Dynamics Code (ACDC) is presented and explored. This program was created to study the first steps of atmospheric new particle formation…”
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From quantum chemical formation free energies to evaporation rates by Ortega, I. K, Kupiainen, O, Kurtén, T, Olenius, T, Wilkman, O, McGrath, M. J, Loukonen, V, Vehkamäki, H

“…Atmospheric new particle formation is an important source of atmospheric aerosols. Large efforts have been made during the past few years to identify which…”
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Amines are likely to enhance neutral and ion-induced sulfuric acid-water nucleation in the atmosphere more effectively than ammonia by Kurtén, T., Loukonen, V., Vehkamäki, H., Kulmala, M.

“…We have studied the structure and formation thermodynamics of dimer clusters containing H2SO4 or HSO4− together with ammonia and seven different amines…”
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Separation of isomers using a differential mobility analyser (DMA): Comparison of experimental vs modelled ion mobility by Bianco, A., Neefjes, I., Alfaouri, D., Vehkamäki, H., Kurtén, T., Ahonen, L., Passananti, M., Kangasluoma, J.

“…Mass spectrometry is uniquely suited to identify and quantify environmentally relevant molecules and molecular clusters. Mass spectrometry alone is, however,…”
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Amine substitution into sulfuric acid – ammonia clusters by Kupiainen, O, Ortega, I. K, Kurtén, T, Vehkamäki, H

“…The substitution of ammonia by dimethylamine in sulfuric acid – ammonia – dimethylamine clusters was studied using a collision and evaporation dynamics model…”
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Formation and growth rates of ultrafine atmospheric particles: a review of observations by Kulmala, M., Vehkamäki, H., Petäjä, T., Dal Maso, M., Lauri, A., Kerminen, V.-M., Birmili, W., McMurry, P.H.

“…Over the past decade, the formation and growth of nanometer-size atmospheric aerosol particles have been observed at a number of sites around the world…”
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Electrical charging changes the composition of sulfuric acid–ammonia/dimethylamine clusters by Ortega, I. K, Olenius, T, Kupiainen-Määttä, O, Loukonen, V, Kurtén, T, Vehkamäki, H

“…Sulfuric acid clusters stabilized by base molecules are likely to have a significant role in atmospheric new-particle formation. Recent advances in mass…”
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Composition and temporal behavior of ambient ions in the boreal forest by Ehn, M., Junninen, H., Petäjä, T., Kurtén, T., Kerminen, V.-M., Schobesberger, S., Manninen, H. E., Ortega, I. K., Vehkamäki, H., Kulmala, M., Worsnop, D. R.

“…A recently developed atmospheric pressure interface mass spectrometer (APi-TOF) measured the negative and positive ambient ion composition at a boreal forest…”
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On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation by Paasonen, P, Olenius, T, Kupiainen, O, Kurtén, T, Petäjä, T, Birmili, W, Hamed, A, Hu, M, Huey, L. G, Plass-Duelmer, C, Smith, J. N, Wiedensohler, A, Loukonen, V, McGrath, M. J, Ortega, I. K, Laaksonen, A, Vehkamäki, H, Kerminen, V.-M, Kulmala, M

“…Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate…”
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Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase by Tsona, N. T, Bork, N, Vehkamäki, H

“…The gas phase reaction between SO4−(H2O)n and SO2, n = 0–2, is investigated using ab initio calculations and kinetic modelling. Structures of reactants,…”
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Exploring the atmospheric chemistry of O2SO3− and assessing the maximum turnover number of ion-catalysed H2SO4 formation by N. Bork, T. Kurtén, H. Vehkamäki

“…It has recently been demonstrated that the O2SO3− ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density…”
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The effect of H2SO4 - amine clustering on chemical ionization mass spectrometry (CIMS) measurements of gas-phase sulfuric acid by Kurtén, T, Petäjä, T, Smith, J, Ortega, I K, Sipilä, M, Junninen, H, Ehn, M, Vehkamäki, H, Mauldin, L, Worsnop, D R, Kulmala, M

“…The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS) based on nitrate reagent ions. We…”
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An improved parameterization for sulfuric acid–water nucleation rates for tropospheric and stratospheric conditions by Vehkamäki, H., Kulmala, M., Napari, I., Lehtinen, K. E. J., Timmreck, C., Noppel, M., Laaksonen, A.

“…In this paper we present parameterized equations for calculation of sulfuric acid–water critical nucleus compositions, critical cluster radii and homogeneous…”
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Proton affinities of candidates for positively charged ambient ions in boreal forests by Ruusuvuori, K, Kurtén, T, Ortega, I. K, Faust, J, Vehkamäki, H

“…The optimized structures and proton affinities of a total of 81 nitrogen-containing bases, chosen based on field measurements of ambient positive ions, were…”
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Parametrization of ternary nucleation rates for H2SO4-NH3-H2O vapors by Napari, I., Noppel, M., Vehkamäki, H., Kulmala, M.

“…A parametrization of nucleation rates for H2O‐H2SO4‐NH3 vapors in atmospheric conditions is developed. The parametrization is based on nucleation rates…”
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Fatty acids on continental sulfate aerosol particles by Tervahattu, H., Juhanoja, J., Vaida, V., Tuck, A. F., Niemi, J. V., Kupiainen, K., Kulmala, M., Vehkamäki, H.

“…Surface analyses of atmospheric aerosols from different continental sources, such as forest fires and coal and straw burning, show that organic surfactants are…”
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Atmospheric nucleation: highlights of the EUCAARI project and future directions by Kerminen, V.-M., Petäjä, T., Manninen, H. E., Paasonen, P., Nieminen, T., Sipilä, M., Junninen, H., Ehn, M., Gagné, S., Laakso, L., Riipinen, I., Vehkamäki, H., Kurten, T., Ortega, I. K., Dal Maso, M., Brus, D., Hyvärinen, A., Lihavainen, H., Leppä, J., Lehtinen, K. E. J., Mirme, A., Mirme, S., Hõrrak, U., Berndt, T., Stratmann, F., Birmili, W., Wiedensohler, A., Metzger, A., Dommen, J., Baltensperger, U., Kiendler-Scharr, A., Mentel, T. F., Wildt, J., Winkler, P. M., Wagner, P. E., Petzold, A., Minikin, A., Plass-Dülmer, C., Pöschl, U., Laaksonen, A., Kulmala, M.

“…Within the project EUCAARI (European Integrated project on Aerosol Cloud Climate and Air Quality interactions), atmospheric nucleation was studied by (i)…”
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The charging of neutral dimethylamine and dimethylamine–sulfuric acid clusters using protonated acetone by Ruusuvuori, K, Hietala, P, Kupiainen-Määttä, O, Jokinen, T, Junninen, H, Sipilä, M, Kurtén, T, Vehkamäki, H

“…Sulfuric acid is generally considered one of the most important substances taking part in atmospheric particle formation. However, in typical atmospheric…”
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