Enhancement of atmospheric nucleation by highly oxygenated organic molecules: a density functional theory study

New particle formation (NPF) by gas–particle conversion is the main source of atmospheric aerosols. Highly oxygenated organic molecules (HOMs) and sulfuric acid (SA) are important NPF participants. 2-Methylglyceric acid (MGA), one kind of HOMs, is a tracer of isoprene-derived SOAs. The nucleation mechanisms of MGA with SA were studied using density functional theory and atmospheric cluster dynamics code kinetic model in this study, along with that of MGA with methanesulfonic acid (MSA) as a comparison. The results imply that the homomolecular nucleation of MGA is unlikely to occur in the atmosphere, and MGA and SA effectively contribute to heteromolecular nucleation mainly in the form of heterodimer. MSA exhibits similar properties to SA in its ability to form clusters with MGA, but is slightly weaker than SA. Our findings provide theoretical support consistent with experimental studies to deepen understanding of the mechanisms by which HOMs enhance atmospheric aerosols.