Heterogeneous Autoxidation of VOCs Promotes Light-Scattering of Atmospheric Mineral Particle: A DFT Study

Recently, the heterogeneous autoxidation of volatile organic compounds (VOCs) has been shown to alter the light-scattering property of atmospheric mineral particles. Here, we investigate how VOCs with different central atoms dictate autoxidation pathways and subsequent highly oxygenated molecules (HOMs) properties, ultimately influencing the complex refractive index of VOC-mineral particles via density functional theory (DFT) and quantitative structure–property relationship (QSPR) analysis. Using dimethylsulfide (DMS)/dimethylether (DME) as ether-type proxies and triethylamine (TEA)/trimethylphosphine (TMP) as alkane-type proxies, we reveal two distinct autoxidation paths: alkane-type VOCs undergo more O₂-addition steps due to their structural capacity for H-shift reactions, generating HOMs with higher oxidation states (OS), molar mass, and polarizability. These properties drive stepwise increases in the refractive index (n) for alkane-VOC-mineral particles, leading to stronger light-scattering ability compared to ether-type counterparts. Our results establish a direct link between VOCs' autoxidation mechanisms and optical properties, providing new insights into climate-relevant aerosol interactions.