Dynamics and Sorption Kinetics of Methanol Monomers and Clusters on Nopinone Surfaces.

Organic-organic interactions play important roles in secondary organic aerosol formation, but the interactions are complex and poorly understood. Here, we use environmental molecular beam experiments combined with molecular dynamics simulations to investigate the interactions between methanol and nopinone, as atmospheric organic proxies. In the experiments, methanol monomers and clusters are sent to collide with three types of surfaces, i.

Experimental and Computational Study of Molecular Water Interactions with Condensed Nopinone Surfaces Under Atmospherically Relevant Conditions.

Water and organics are omnipresent in the atmosphere, and their interactions influence the properties and lifetime of both aerosols and clouds. Nopinone is one of the major reaction products formed from β-pinene oxidation, a compound emitted by coniferous trees, and it has been found in both gas and particle phases in the atmosphere. Here, we investigate the interactions between water molecules and nopinone surfaces by combining environmental molecular beam (EMB) experiments and molecular dynamics (MD) simulations.

Understanding water interactions with organic surfaces: environmental molecular beam and molecular dynamics studies of the water-butanol system.

The interactions between water molecules and condensed n-butanol surfaces are investigated at temperatures from 160 to 240 K using the environmental molecular beam experimental method and complementary molecular dynamics (MD) simulations. In the experiments hyperthermal water molecules are directed onto a condensed n-butanol layer and the flux from the surface is detected in different directions. A small fraction of the water molecules scatters inelastically from the surface while losing 60-90% of their initial kinetic energy in collisions, and the angular distributions of these molecules are broad for both solid and liquid surfaces.

The Dynamics and Kinetics of Water Interactions with a Condensed Nopinone Surface.

Water and organic molecules are omnipresent in the environment, and their interactions are of central importance in many Earth system processes. Here we investigate molecular-level interactions between water and a nopinone surface using an environmental molecular beam (EMB) technique. Nopinone is a major reaction product formed during oxidation of β-pinene, a prominent compound emitted by coniferous trees, which has been found in both the gas and particle phases of atmospheric aerosol.

A novel gas-vacuum interface for environmental molecular beam studies.

Molecular beam techniques are commonly used to obtain detailed information about reaction dynamics and kinetics of gas-surface interactions. These experiments are traditionally performed in vacuum and the dynamic state of surfaces under ambient conditions is thereby excluded from detailed studies. Herein we describe the development and demonstration of a new vacuum-gas interface that increases the accessible pressure range in environmental molecular beam (EMB) experiments.

Water accommodation on ice and organic surfaces: insights from environmental molecular beam experiments.

Water uptake on aerosol and cloud particles in the atmosphere modifies their chemistry and microphysics with important implications for climate on Earth. Here, we apply an environmental molecular beam (EMB) method to characterize water accommodation on ice and organic surfaces. The adsorption of surface-active compounds including short-chain alcohols, nitric acid, and acetic acid significantly affects accommodation of D2O on ice.