We have collected, recomputed, and compiled a database consisting of 633 unique atmospherically relevant molecular clusters containing sulfuric acid, bases, oxidized organic compounds, and water. The ...database is composed of strongly hydrogen-bonded molecular clusters and spans neutral, negatively charged, and positively charged clusters of atmospheric relevance. All the cluster structures and vibrational frequencies have been re-evaluated at the ωB97X-D/6-31++G(d,p) level of theory, and the single point energies have been refined using a high-level DLPNO-CCSD(T)/aug-cc-pVTZ calculation. The database unifies published atmospheric molecular clusters under a single common methodology and serves as an efficient look-up table for molecular cluster structures and thermochemical parameters. Utilizing the database, the performance of four semi-empirical methodologies (PM6, PM7, B97-3c, and PBEh-3c) in calculating the binding energies of atmospheric molecular clusters is assessed. It is identified that the B97-3c and PBEh-3c empirically corrected density functional theory methods yield low errors in the binding energies compared to DLPNO-CCSD(T)/aug-cc-pVTZ reference results and that a simple linear model can be utilized for estimating accurate binding energies based on ωB97X-D/6-31++G(d,p) results.
The role of methanesulfonic acid (MSA) in atmospheric new particle formation remains highly uncertain. Using state-of-the-art computational methods, we study the electrically neutral ...(MSA)0–2(base)0–2 clusters, with base = ammonia (A), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylenediamine (EDA). The cluster configurations are obtained using the ABCluster program and the number of initial cluster configurations is reduced based on PM7 calculations. Thermochemical parameters are calculated using the quasi-harmonic approximation based on the ωB97X-D/6-31++G(d,p) cluster structures and vibrational frequencies. The single point energies are calculated at the DLPNO-CCSD(T0)/aug-cc-pVTZ level of theory. We find that MSA shows a different interaction pattern with the bases compared to sulfuric acid and does not simply follow the basicity of the bases for these small clusters. In all cases, we find that the MSA-base clusters show very low cluster formation potential, indicating that electrically neutral clusters consisting solely of MSA as the clustering acid are most likely not capable of forming and growing under realistic atmospheric conditions.
We recently coined the term clusteromics as a holistic approach for obtaining insight into the chemical complexity of atmospheric molecular cluster formation and at the same time providing the ...foundation for thermochemical databases that can be utilized for developing machine learning models. Here, we present the first paper in the series that applies state-of-the-art computational methods to study multicomponent (SA)0–2(base)0–2 clusters, with SA = sulfuric acid and base = ammonia (A), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylenediamine (EDA) with all combinations of the five bases. The initial cluster configurations are obtained using the ABCluster program and the number of relevant configurations are reduced based on PM7 and ωB97X-D/6-31++G(d,p) calculations. Thermochemical parameters are calculated based on the ωB97X-D/6-31++G(d,p) cluster structures and vibrational frequencies using the quasi-harmonic approximation. The single-point energies are refined with a high-level DLPNO-CCSD(T0)/aug-cc-pVTZ calculation. Using the calculated thermochemical data, we perform kinetics simulations to evaluate the potential of these small (SA)0–2(base)0–2 clusters to grow into larger cluster sizes. In all cases we find that having more than one type of base molecule present in the cluster will increase the potential for forming larger clusters primarily due to the increased available vapor concentration.
This work assesses the performance of DLPNO-CCSD(T0), DLPNO-MP2, and density functional theory methods in calculating the binding energies of a representative test set of 45 atmospheric acid–acid, ...acid–base, and acid–water dimer clusters. The performance of the approximate methods is compared to high level explicitly correlated CCSD(F12*)(T)/complete basis set (CBS) reference calculations. Out of the tested density functionals, ωB97X-D3(BJ) shows the best performance with a mean deviation of 0.09 kcal/mol and a maximum deviation of 0.83 kcal/mol. The RI-CC2/aug-cc-pV(T+d)Z level of theory severely overpredicts the cluster binding energies with a mean deviation of −1.31 kcal/mol and a maximum deviation up to −3.00 kcal/mol. Hence, RI-CC2/aug-cc-pV(T+d)Z should not be utilized for studying atmospheric molecular clusters. The DLPNO variants are tested both with and without the inclusion of explicit correlation (F12) in the wavefunction, with different pair natural orbital (PNO) settings (loosePNO, normalPNO, and tightPNO) and using both double and triple zeta basis sets. The performance of the DLPNO-MP2 methods is found to be independent of PNO settings and yield low mean deviations of −0.84 kcal/mol or below. However, DLPNO-MP2 requires explicitly correlated wavefunctions to yield maximum deviations below 1.40 kcal/mol. For obtaining high accuracy, with maximum deviation below ∼1.0 kcal/mol, either DLPNO-CCSD(T0)/aug-cc-pVTZ (normalPNO) calculations or DLPNO-CCSD(T0)-F12/cc-pVTZ-F12 (normalPNO) calculations are required. The most accurate level of theory is found to be DLPNO-CCSD(T0)-F12/cc-pVTZ-F12 using a tightPNO criterion which yields a mean deviation of 0.10 kcal/mol, with a maximum deviation of 0.20 kcal/mol, compared to the CCSD(F12*)(T)/CBS reference.
Diamines Can Initiate New Particle Formation in the Atmosphere Elm, Jonas; Passananti, Monica; Kurtén, Theo ...
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
08/2017, Letnik:
121, Številka:
32
Journal Article
Recenzirano
Odprti dostop
Recent experimental evidence suggests that diamines can enhance atmospheric new particle formation more efficiently compared to monoamines such as dimethylamine. Here we investigate the molecular ...interactions between sulfuric acid (sa) and the diamine putrescine (put) using computational methods. The molecular structure of up to four sulfuric acid molecules and up to four putrescine molecules were obtained at the ωB97X-D/6-31++G(d,p) level of theory. We utilized a domain local pair natural orbital coupled cluster method (DLPNO-CCSD(T)/aug-cc-pVTZ) to obtain highly accurate binding energies of the clusters. We find that the (sa)1–4(put)1–4 clusters show more ionic character than clusters consisting of sulfuric acid and dimethylamine (dma) by readily forming several sulfate ions in the cluster. To estimate the stability of the clusters, we calculate the evaporation rates and compare them to ESI-APi-TOF measurements. Using the atmospheric cluster dynamics code (ACDC), we simulate and compare the new particle formation rates between the (sa)1–4(put)1–4 and (sa)1–4(dma)1–4 cluster systems. We find that putrescine significantly enhances the formation of new particles compared to dimethylamine. Our findings suggest that a large range of amines with different basicity is capable of explaining various regions of the observed new particle formation events. These results indicate that diamines, or related compounds with high basicity, might be important species in forming the initial cluster with sulfuric acid and subsequently more abundant amines with lower basicity can assist in the new particle formation process by attaching to the sulfuric acid–diamine nucleus.
Amines are recognized as significant enhancing species on methanesulfonic acid (MSA)-driven new particle formation (NPF). Monoethanolamine (MEA) has been detected in the atmosphere, and its ...concentration could be significantly increased once MEA-based postcombustion CO2 capture technology is widely implemented. Here, we evaluated the enhancing potential of MEA on MSA-driven NPF by examining the formation of MEA–MSA clusters using a combination of quantum chemical calculations and kinetics modeling. The results indicate that the −OH group of MEA can form at least one hydrogen bond with MSA or MEA in all MEA-containing clusters. The enhancing potential of MEA is higher than that of the strongest enhancing agent known so far, methylamine (MA), for MSA-driven NPF. Such high enhancing potential can be ascribed to not only the higher gas-phase basicity but also the role of the additional −OH group of MEA in increasing the binding free energy by forming additional hydrogen bonds. This clarifies the importance of hydrogen-bonding capacity from the nonamino group of amines in enhancing MSA-driven NPF. The main growth pathway for MEA–MSA clusters proceeds via the initial formation of the (MEA)1(MSA)1 cluster, followed by alternately adding one MSA and one MEA molecule, differing from the case of MA–MSA clusters.
Atmospheric amines can enhance methanesulfonic acid (MSA)-driven new particle formation (NPF), but the mechanism is fundamentally different compared to that of the extensively studied sulfuric acid ...(SA)-driven process. Generally, the enhancing potentials of amines in SA-driven NPF follow the basicity, while this is not the case for MSA-driven NPF, where structural effects dominate, making MSA-driven NPF more prominent for methylamine (MA) compared to dimethylamine (DMA). Therefore, probing structural factors determining the enhancing potentials of amines on MSA-driven NPF is key to fully understanding the contribution of MSA to NPF. Here, we performed a comparative study on DMA and MA enhancing MSA-driven NPF by examining cluster formation using computational methods. The results indicate that DMA–MSA clusters are more stable than the corresponding MA–MSA clusters for cluster sizes up to (DMA)2(MSA)2, indicating that the basicity of amines dominates the initial cluster formation. The methyl groups of DMA were found to present significant steric hindrance beyond the (DMA)2(MSA)2 cluster and this adds to the lower hydrogen bonding capacity of DMA, making the cluster growth less favorable compared to MA. This study implies that several amines could synergistically enhance MSA-driven NPF by maximizing the advantage of different amines in different amine–MSA cluster growth stages.
The molecular interactions between sulfuric acid (sa) and methylamine (ma) are investigated using computational methods. The molecular structures and vibrational frequencies of (sa) a (ma) b ...clusters, with a, b ≤ 4, were obtained with the ωB97X-D functional using a 6-31++G(d,p) basis set. The single-point energies were corrected using the domain-based local pair natural orbital coupled cluster methodDLPNO–CCSD(T)with an aug-cc-pVTZ basis set. The calculated Gibbs free energies (Δ G ) of the clusters are used to calculate the evaporation rates of the (sa) a (ma) b cluster system and compare them to the corresponding ammonia clusters. With the atmospheric cluster dynamics code (ACDC), the new particle formation rates of the (sa) a (ma) b clusters were simulated and compared to the (sa) a (dma) b cluster system. It is found that methylamine is not capable of explaining observed new particle formation event in the ambient atmosphere. Looking into the calculated Gibbs free energy profiles it is found that the limiting steps in forming stable (sa)3–4(base)3–4 clusters depend strongly on the formation of the (sa)1(base)1 and (sa)2(base)2 clusters. These findings further support that compounds with high basicity are required to form the very initial cluster nucleus, which serves as the basis for forming new particles in the atmosphere.
The formation of atmospheric molecular clusters is an important stage in forming new particles in the atmosphere. Despite being a highly focused research area, the exact chemical species involved in ...the initial steps in new particle formation remain elusive. In this Perspective the main challenges and recent progression in the field are outlined with a special emphasis on the chemical complexity of the puzzle and prospect of modeling larger clusters. In general, there is a high demand for accurate and more complete quantum chemical data sets that can be applied in cluster distribution dynamics models and coupled to atmospheric chemical transport models. A view on how the community could reach this goal by applying data-driven machine learning approaches for more efficient exploration of cluster configurations is presented. A path toward larger clusters and direct molecular dynamics simulations of cluster formation and growth using machine learning models is discussed.
Over Boreal regions, monoterpenes emitted from the forest are the main precursors for secondary organic aerosol (SOA) formation and the primary driver of the growth of new aerosol particles to ...climatically important cloud condensation nuclei (CCN). Autoxidation of monoterpenes leads to rapid formation of Highly Oxygenated organic Molecules (HOM). We have developed the first model with near-explicit representation of atmospheric new particle formation (NPF) and HOM formation. The model can reproduce the observed NPF, HOM gas-phase composition and SOA formation over the Boreal forest. During the spring, HOM SOA formation increases the CCN concentration by ~10 % and causes a direct aerosol radiative forcing of -0.10 W/m
. In contrast, NPF reduces the number of CCN at updraft velocities < 0.2 m/s, and causes a direct aerosol radiative forcing of +0.15 W/m
. Hence, while HOM SOA contributes to climate cooling, NPF can result in climate warming over the Boreal forest.
PDF
