Anomalously Strong Effect of the Ion Sign on the Thermochemistry of Hydrogen Bonded Aqueous Clusters of Identical Chemical Composition

Nadykto, Alexey B.; Yu, Fangqun; Natsheh, Anas Al

doi:10.3390/ijms10020507

Cited by 8 publications

(5 citation statements)

References 24 publications

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“…We have chosen to hydrate the singly charged ions by three water molecules and the doubly charged ions with six water molecules to be certain that there are no errors due to electron detachment. The structure of the ion–water clusters have in several cases previously been identified and were extracted from the following publications: (Cl – )(H 2 O) n from Nadykto et al, (NO 3 – )(H 2 O) n from Liu et al, (NH 4 + )(H 2 O) n from Pickard et al, and (SO 4 2– )(H 2 O) n from Lambrecht et al In the case of the (Na + )(H 2 O) 3 cluster, we were unable to find any literature structure, and it was therefore manually constructed. For details of the construction and configurational sampling of the monohydrate-ion–water clusters, the SI and the references cited therein.…”

Section: Methodsmentioning

confidence: 99%

Glyoxal and Methylglyoxal Setschenow Salting Constants in Sulfate, Nitrate, and Chloride Solutions: Measurements and Gibbs Energies

Waxman

Elm

Kurtén

et al. 2015

Environ. Sci. Technol.

133

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Knowledge about Setschenow salting constants, KS, the exponential dependence of Henry's Law coefficients on salt concentration, is of particular importance to predict secondary organic aerosol (SOA) formation from soluble species in atmospheric waters with high salt concentrations, such as aerosols. We have measured KS of glyoxal and methylglyoxal for the atmospherically relevant salts (NH4)2SO4, NH4NO3, NaNO3, and NaCl and find that glyoxal consistently "salts-in" (KS of -0.16, -0.06, -0.065, -0.1 molality(-1), respectively) while methylglyoxal "salts-out" (KS of +0.16, +0.075, +0.02, +0.06 molality(-1)). We show that KS values for different salts are additive and present an equation for use in atmospheric models. Additionally, we have performed a series of quantum chemical calculations to determine the interactions between glyoxal/methylglyoxal monohydrate with Cl(-), NO3(-), SO4(2-), Na(+), and NH4(+) and find Gibbs free energies of water displacement of -10.9, -22.0, -22.9, 2.09, and 1.2 kJ/mol for glyoxal monohydrate and -3.1, -10.3, -7.91, 6.11, and 1.6 kJ/mol for methylglyoxal monohydrate with uncertainties of 8 kJ/mol. The quantum chemical calculations support that SO4(2-), NO3(-), and Cl(-) modify partitioning, while cations do not. Other factors such as ion charge or partitioning volume effects likely need to be considered to fully explain salting effects.

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Section: Methodsmentioning

confidence: 99%

Glyoxal and Methylglyoxal Setschenow Salting Constants in Sulfate, Nitrate, and Chloride Solutions: Measurements and Gibbs Energies

Waxman

Elm

Kurtén

et al. 2015

Environ. Sci. Technol.

133

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“…Quantum chemistry calculations have also been used to investigate the underlying mechanism relevant to ion-induced nucleation for which sufficient experimental data exist on the thermochemistry of HSO 4 – -based and H 2 S 2 O 7 – -based ion clusters. Nadykto et al , showed that the sign preference in ion-induced nucleation, which manifests itself in water preferring to nucleate more efficiently on negatively charged ions, arises from the molecular structure of small charged clusters and can be explained and predicted by quantum chemical calculations. Furthermore, the stabilizing effect of ammonia on formation of negatively charged cluster hydrates is ruled out .…”

Section: Nucleation Of Nanoparticles In the Atmospherementioning

confidence: 99%

Nucleation and Growth of Nanoparticles in the Atmosphere

et al. 2011

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“…37 They have argued that cations are more effective nucleation enhancers than anions due to quantum effects that are included in their DFT model but neglected in empirical models. [37][38][39] The most significant limitation of both ab initio and mass spectrometry data is their relatively small range of accessible cluster sizes. Mass spectrometry data can only be obtained for clusters sufficiently stable to be found in measurable concentrations, while ab initio calculations for larger clusters require tremendous amounts of computational effort.…”

Section: Introductionmentioning

confidence: 99%

Sign preference in ion-induced nucleation: Contributions to the free energy barrier

Keasler

Kim

Chen

2012

The Journal of Chemical Physics

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We have performed a series of computer simulations using the AVUS-HR approach to better understand the origin of the sign preference in ion-induced nucleation. In particular, we emphasize the importance of distinguishing between the total formation free energy of a cluster, and the nucleation free energy, which involves only those steps contributing to the free energy barrier. We have separately considered how the ion-water potential energy, the water-water potential energy, and the entropy contribute to both the cluster formation free energy, and the nucleation free energy. These simulations have shown that while the ion-water potential energies make the largest contribution to the formation free energy difference between positive and negative ions, the entropy is the contribution leading to lower nucleation free energy barriers for negative ions. The primary reason for this is the larger stable (but precritical) clusters formed around negative ions. We have further shown that the distinction between formation and nucleation free energies is of particular importance when comparing small cations with larger anions where the formation free energies can be much lower for the cationic clusters, even though the nucleation barriers are lower for the anionic clusters.

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Anomalously Strong Effect of the Ion Sign on the Thermochemistry of Hydrogen Bonded Aqueous Clusters of Identical Chemical Composition

Cited by 8 publications

References 24 publications

Glyoxal and Methylglyoxal Setschenow Salting Constants in Sulfate, Nitrate, and Chloride Solutions: Measurements and Gibbs Energies

Glyoxal and Methylglyoxal Setschenow Salting Constants in Sulfate, Nitrate, and Chloride Solutions: Measurements and Gibbs Energies

Nucleation and Growth of Nanoparticles in the Atmosphere

Sign preference in ion-induced nucleation: Contributions to the free energy barrier

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