Computational Study of the Effect of Mineral Dust on Secondary Organic Aerosol Formation by Accretion Reactions of Closed-Shell Organic Compounds

Abstract

The effect of dust aerosols on accretion reactions of water, formaldehyde and formic acid was studied in the conditions of Earth's troposphere using at the DLPNO-CCSD(T)/aug-cc-pVTZ//ωB97X-D/6-31++G** level of theory. Detailed analysis of the reaction mechanisms in the gas phase and on the surface of mineral dust, represented by mono-and tri-silicic acid, revealed that mineral dust has the potential for decreasing reaction barrier heights. Specifically, at 0 K, mineral dust can lower the apparent energy barrier of the reaction of formaldehyde with formic acid to zero. However, when the entropic contributions to the reaction free energies were accounted for, mineral dust was found to selectively enhance the reaction of water with formaldehyde, while inhibiting the reaction of formaldehyde and formic acid, in the lower parts of the troposphere (with temperatures around 298 K). In the upper troposphere (with temperatures closer to 198 K), mineral dust catalyzes both reactions, and also the reaction of methanol with formic acid. Despite the intrinsic potential of mineral dust, calculation of the catalytic enhancement parameter for a likely range of dust aerosol concentrations suggested that dust aerosols will not contribute to secondary organic aerosol formation via dimerization of closed-shell organic compounds. The main reason for this is the relatively low absolute concentration of tropospheric dust aerosol, and its inefficiency in increasing the effective reaction rate coefficients.

Global optimization of chemical cluster structures: Methods, applications, and challenges

“…The development of GO as implemented in ABCluster, has eliminated this obstacle to a large extent, making a series of productive NPF studies possible [32, 96, 167, 172–197] and revealing valuable insights into atmospheric chemistry (see Figure 7 for some examples). ABCluster has been regarded as a standard tool in this field [198–200].…”

The Kinetics of Adsorption and Desorption of Selected Semivolatile Hydrocarbons and H2O Vapor on Two Mineral Dust Materials: A Molecular View

“…Many of the simple components of mineral dust by themselves, such as α-Al 2 O 3 , SiO 2 , TiO 2 , α-Fe 2 O 3 , feldspars, carbonates, sulfates, or most importantly NH 3 -deactivated ATD, had observed rate constants smaller by up to 3 orders of magnitude compared to Chinese desert dust (CDD), montmorillonites, or ATD. This fact complicates the investigations but throws us in the right direction compared to the long-held view that the reactivity of mineral dust followed the mixing ratio of its components as in Usher et al This result also puts a question mark on the theoretical approach taken by Keshavarz et al who took ortho -silicic or trisilicic acid as a surrogate for mineral dust materials, which is a truly questionable approach given the conclusions of Kameda et al…”

“…In addition, using pyridine adsorption monitored using IR DRIFTS, the authors showed that the nitration reaction was accelerated, especially on clay mineral substrates, which underlines the necessity of providing acidic sites for efficient nitration. Many of the simple components of This fact complicates the investigations but throws us in the right direction compared to the long-held view that the reactivity of mineral dust followed the mixing ratio of its components as in Usher et al 2 This result also puts a question mark on the theoretical approach taken by Keshavarz et al 23 who took ortho-silicic or trisilicic acid as a surrogate for mineral dust materials, which is a truly questionable approach given the conclusions of Kameda et al 41 The important group of main messages resulting from our current work that we have formulated in the next section are for the moment unmatched in that these data fill a critical gap in terms of the variability of coverage, as uncertain it may be in terms of numerical accuracy. This holds both for the uptake and for the initial uptake and desorption kinetics (k a , k 0 , and γ 0 ).…”

“…A relatively new aspect of studying the chemical kinetics of reactions on or in the presence of aerosol interfaces is represented by numerical electronic structure calculations using quantum chemical methods. 23 The goal of these studies is the investigation of accretion (dimerization) reactions on the The Journal of Physical Chemistry A interface of model or surrogate mineral dust substrates, for instance, those represented by silicic or trisilicic acid simulating quartz and feldspars. Accretion reactions are closed-shell processes that have high barriers and are therefore good candidates for examining catalytic activity on mineral dust surfaces.…”

“…A relatively new aspect of studying the chemical kinetics of reactions on or in the presence of aerosol interfaces is represented by numerical electronic structure calculations using quantum chemical methods. 23 The goal of these studies is the investigation of accretion (dimerization) reactions on the ), the addition of H 2 O to formaldehde to yield the gem-diol of formaldehde, and the aldol condensation of methanol with formic acid. Although reaction barriers are lower at the interface, no convincing example of rate acceleration on mineral dust model substrates has emerged so far.…”