Molecular dynamics simulations of atmospherically relevant molecular clusters: a case study of nitrate ion complexes

Abstract

The formation and decomposition of complexes of ions with atmospheric analyte molecules are key processes in chemical ionization mass spectrometry (CIMS) instruments, as well as in atmospheric new particle formation (NPF). In this study, we conduct extensive molecular dynamics (MD) simulations of the decomposition of already-formed molecular complexes with nitrate ions (NO₃⁻). We study purely thermal decomposition in vacuo and in the presence of nitrogen gas, as well as the decomposition driven by electric-field induced collisions with nitrogen gas. Our findings are relevant to improving the understanding of basic processes taking place in CIMS as well as in other MS instruments more generally.