title: Near-unity mass accommodation coefficient of organic molecules of varying structure.
abstract: Atmospheric aerosol particles have a significant effect on global climate, air quality, and consequently human health. Condensation of organic vapors is a key process in the growth of nanometer-sized particles to climate relevant sizes. This growth is very sensitive to the mass accommodation coefficient α, a quantity describing the vapor uptake ability of the particles, but knowledge on α of atmospheric organics is lacking. In this work, we have determined α for four organic molecules with diverse structural properties: adipic acid, succinic acid, naphthalene, and nonane. The coefficients are studied using molecular dynamics simulations, complemented with expansion chamber measurements. Our results are consistent with α = 1 (indicating nearly perfect accommodation), regardless of the molecular structural properties, the phase state of the bulk condensed phase, or surface curvature. The results highlight the need for experimental techniques capable of resolving the internal structure of nanoparticles to better constrain the accommodation of atmospheric organics.
authors.affiliation: Department of Applied Environmental Science and Bolin Centre for Climate Research, Stockholm University , SE-10691 Stockholm, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Julin
authors.forename: Paul M
authors.initials: PM
authors.lastname: Winkler
authors.forename: Neil M
authors.initials: NM
authors.lastname: Donahue
authors.forename: Paul E
authors.initials: PE
authors.lastname: Wagner
authors.forename: Ilona
authors.initials: I
authors.lastname: Riipinen
mesh_terms: D000272:Adipates / Q000737:chemistry*; D000336:Aerosols / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry*; D002980:Climate; D005740:Gases / Q000737:chemistry; D006801:Humans; D056004:Molecular Dynamics Simulation; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry; D009281:Naphthalenes / Q000737:chemistry*; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D019802:Succinic Acid / Q000737:chemistry*
chemical_list: D000272:Adipates; D000336:Aerosols; D000473:Alkanes; D005740:Gases; D009281:Naphthalenes; D052638:Particulate Matter; C031721:naphthalene; C029900:adipic acid; D019802:Succinic Acid; C017573:nonane