Hydration of Atmospheric Molecular Clusters II: Organic Acid-Water Clusters

Jens Vive Kildgaard, Kurt V. Mikkelsen*, Merete Bilde, Jonas Elm

*Corresponding author for this work

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Abstract

Using computational methods we study the gas phase hydration of three different atmospherically relevant organic acids with up to 10 water molecules. We study the di- carboxylic acid (pinic acid) and a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid (mbtca)) that are both identified as products from α-pinene oxidation reactions. We also study an 2-oxohexanediperoxy acid (ohdpa) that have been identified as a prod- uct from cyclohexene autoxidation. To sample the cluster structures, we employ our recently developed systematic hydrate sampling technique and identify a total of 551 hydrate clusters. The cluster structures and thermochemical parameters (at 298.15 K and 1 atm) are obtained at the ωB97X-D/6-31++G(d,p) level of theory and the single point energy of the clusters have been refined using a high level DLPNO-CCSD(T)/aug- cc-pVTZ calculation. We find that all three tested organic acids interact significantly weaker with water compared to the primary nucleation precursor sulfuric acid. Even at 100% relative humidity (298.15 K and 1 atm), we find that ohdpa remains unhydrated and only the monohydrate of pinic acid and mbtca are slightly populated (4% and 2%, respectively). From the obtained molecular structures potential implications for ice nucleating ability of aerosol particles is discussed.
Original languageEnglish
JournalJournal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
Volume142
Issue number43
Pages (from-to)8549-8556
ISSN1089-5639
DOIs
Publication statusPublished - 2018

Cite this

@article{414cb9287426497d94ff9c73b57f530f,
title = "Hydration of Atmospheric Molecular Clusters II: Organic Acid-Water Clusters",
abstract = "Using computational methods we study the gas phase hydration of three different atmospherically relevant organic acids with up to 10 water molecules. We study the di- carboxylic acid (pinic acid) and a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid (mbtca)) that are both identified as products from α-pinene oxidation reactions. We also study an 2-oxohexanediperoxy acid (ohdpa) that have been identified as a prod- uct from cyclohexene autoxidation. To sample the cluster structures, we employ our recently developed systematic hydrate sampling technique and identify a total of 551 hydrate clusters. The cluster structures and thermochemical parameters (at 298.15 K and 1 atm) are obtained at the ωB97X-D/6-31++G(d,p) level of theory and the single point energy of the clusters have been refined using a high level DLPNO-CCSD(T)/aug- cc-pVTZ calculation. We find that all three tested organic acids interact significantly weaker with water compared to the primary nucleation precursor sulfuric acid. Even at 100{\%} relative humidity (298.15 K and 1 atm), we find that ohdpa remains unhydrated and only the monohydrate of pinic acid and mbtca are slightly populated (4{\%} and 2{\%}, respectively). From the obtained molecular structures potential implications for ice nucleating ability of aerosol particles is discussed.",
author = "Kildgaard, {Jens Vive} and Mikkelsen, {Kurt V.} and Merete Bilde and Jonas Elm",
year = "2018",
doi = "10.1021/acs.jpca.8b07713",
language = "English",
volume = "142",
pages = "8549--8556",
journal = "Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory",
issn = "1089-5639",
publisher = "American Chemical Society",
number = "43",

}

Hydration of Atmospheric Molecular Clusters II: Organic Acid-Water Clusters. / Kildgaard, Jens Vive; Mikkelsen, Kurt V.; Bilde, Merete ; Elm, Jonas.

In: Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory, Vol. 142, No. 43, 2018, p. 8549-8556.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Hydration of Atmospheric Molecular Clusters II: Organic Acid-Water Clusters

AU - Kildgaard, Jens Vive

AU - Mikkelsen, Kurt V.

AU - Bilde, Merete

AU - Elm, Jonas

PY - 2018

Y1 - 2018

N2 - Using computational methods we study the gas phase hydration of three different atmospherically relevant organic acids with up to 10 water molecules. We study the di- carboxylic acid (pinic acid) and a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid (mbtca)) that are both identified as products from α-pinene oxidation reactions. We also study an 2-oxohexanediperoxy acid (ohdpa) that have been identified as a prod- uct from cyclohexene autoxidation. To sample the cluster structures, we employ our recently developed systematic hydrate sampling technique and identify a total of 551 hydrate clusters. The cluster structures and thermochemical parameters (at 298.15 K and 1 atm) are obtained at the ωB97X-D/6-31++G(d,p) level of theory and the single point energy of the clusters have been refined using a high level DLPNO-CCSD(T)/aug- cc-pVTZ calculation. We find that all three tested organic acids interact significantly weaker with water compared to the primary nucleation precursor sulfuric acid. Even at 100% relative humidity (298.15 K and 1 atm), we find that ohdpa remains unhydrated and only the monohydrate of pinic acid and mbtca are slightly populated (4% and 2%, respectively). From the obtained molecular structures potential implications for ice nucleating ability of aerosol particles is discussed.

AB - Using computational methods we study the gas phase hydration of three different atmospherically relevant organic acids with up to 10 water molecules. We study the di- carboxylic acid (pinic acid) and a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid (mbtca)) that are both identified as products from α-pinene oxidation reactions. We also study an 2-oxohexanediperoxy acid (ohdpa) that have been identified as a prod- uct from cyclohexene autoxidation. To sample the cluster structures, we employ our recently developed systematic hydrate sampling technique and identify a total of 551 hydrate clusters. The cluster structures and thermochemical parameters (at 298.15 K and 1 atm) are obtained at the ωB97X-D/6-31++G(d,p) level of theory and the single point energy of the clusters have been refined using a high level DLPNO-CCSD(T)/aug- cc-pVTZ calculation. We find that all three tested organic acids interact significantly weaker with water compared to the primary nucleation precursor sulfuric acid. Even at 100% relative humidity (298.15 K and 1 atm), we find that ohdpa remains unhydrated and only the monohydrate of pinic acid and mbtca are slightly populated (4% and 2%, respectively). From the obtained molecular structures potential implications for ice nucleating ability of aerosol particles is discussed.

U2 - 10.1021/acs.jpca.8b07713

DO - 10.1021/acs.jpca.8b07713

M3 - Journal article

C2 - 30351100

VL - 142

SP - 8549

EP - 8556

JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

SN - 1089-5639

IS - 43

ER -