Microscopic Insights Into the Formation of Methanesulfonic Acid–Methylamine–Ammonia Particles Under Acid-Rich Conditions

Understanding the microscopic mechanisms of new particle formation under acid-rich conditions is significance in atmospheric science. Using quantum chemistry calculations, we investigated mechanism methanesulfonic acid (MSA)–methylamine (MA)–ammonia (NH 3 ) clusters. We focused on binary (MSA) 2n -(MA) n and ternary 3n -(NH , ( = 1–4) systems which contain more than base molecules. found that lowest-energy isomers each system possess considerable thermodynamic dynamic stabilities. In studied cluster structures, all bases are protonated, they form stable ion pairs with MSA, contribute to charge transfer stability MA NH have a synergistic effect NPF conditions, role becomes remarkable as size increases. The excess MSA molecules does not only enhance clusters, but provides potential sites for further growth.