Recent advances in computational chemistry and physics have enabled fully ab initio cluster formation simulations, crucial for understanding aerosol nucleation. However, challenges remain in combining quantum-level theory with molecular dynamics (MD) simulations. A key issue is the classical treatment of atomic motion in MD, which can misrepresent energy distribution, artificially accelerating processes like evaporation. Additionally, thermostatting algorithms, while maintaining temperature, may introduce unphysical effects. These concerns are particularly relevant in atmospheric nucleation studies, where best practices are still evolving. Addressing these methodological challenges will improve simulation accuracy, ensuring better representation of real-world processes and advancing aerosol science.

The diffusivity of aerosol nanoparticles (NPs) under 5 nm is crucial for nanotechnology and aerosol science yet remains unclear. Experiments used micron-sized particles at low pressures to achieve high Knudsen numbers, overlooking the critical atomic-level interactions. Here, molecular dynamics simulations provide diffusivities of fullerene and silica NPs (0.4 to 7 nm) in air, accounting for detailed structure and force fields. Below 3 nm, NP-diffusivities align well with gas diffusivity correlations but deviate from classic equations like Epstein and Stokes-Cunningham-Millikan for particle diffusivity. Differences become more pronounced as NPs approach gas-molecule sizes, while above 5 nm, NP-diffusivities converge with classic equations.

Aerosol Spray Pyrolysis (ASP) is an efficient method for synthesizing iron-based nanoparticles, which are widely used in biomedicine and catalysis. The characteristics of resulting nanoparticles, including size and structure, depend on precursor composition and processing conditions. This study uses molecular dynamics (MD) simulations to investigate nanodroplet evaporation process that leads to nanoparticle formation. Results show iron ions precipitate on the droplet surface, forming a core-shell structure, with Fe³⁺ from iron nitrate favoring this formation more than iron chloride. The MD model results aligns well with experiments and provides insights into key parameters like diffusivity and evaporation, which are difficult to measure experimentally.

This presentation highlights the role of external charging in flame synthesis and its impact on the evolution of nanoparticles generated in the system. The study focused on MgO nanoparticles formed during magnesium combustion. Negative ion emission resulted in partial melting of nanoparticles, while positive ions had little effect. Numerical estimates showed that the observed effect was possible due to the influence of external charging on the thermionic emission of electrons from growing nanoparticles, which could play a significant role in the overall heat exchange. This emphasizes the need to consider the corresponding gas-nanoparticle heat transfer channel in accurate modeling.