Atmospheric Aerosol Nucleation: A Methodological Review of Theoretical Calculations and Molecular Simulation

Abstract

Atmospheric aerosols play a crucial role in large-scale precipitation, global climate change, and Earth’s radiative balance, with new particle formation (NPF) constituting a major source of aerosol particles. NPF is a gas-to-particle phase transition process that involves both the formation of critical clusters—commonly referred to as nucleation—and the subsequent growth of these clusters into larger particles. Theoretical and computational approaches, including quantum chemistry calculations and molecular dynamics simulations, enable investigations of NPF at the microscopic molecular level and provide fundamental insights into the mechanisms governing cluster formation. When combined with cluster dynamics models, these methods further allow quantitative assessments of the atmospheric relevance of proposed nucleation mechanisms. In recent years, machine learning techniques have also emerged as powerful tools for accelerating and optimizing these workflows. In this review, we summarize recent theoretical and computational studies on aerosol nucleation mechanisms from the perspective of molecular clusters. Particular emphasis is placed on classical and representative applications of theoretical methods in nucleation research, including configurational sampling, thermodynamics, and cluster dynamics. We aim for this review to provide a comprehensive overview of the current progress in theoretical and computational nucleation studies, while also highlighting emerging challenges and future research directions in the field.