Current Research Topics and Tools
Trapping of Droplets
We design and build quadrupole traps to electrodynamically levitate droplets arrays. These clouds of trapped droplets allow us to measure heterogeneous reactions over long timescales (days) that more closely approximate the atmosphere.
We use high speed collisions of micron-sized droplets to initiate a chemical reaction (such as the pH jump, which turns on a fluorescent dye as shown above). Droplet collisions enable fast mixing of reactants and allows us the possibility to observe transient intermediates produced in bimolecular condensed phase reactions.
We use a variety of commercial and home-built instrumentation to do our research
Vacuum Ultraviolet (VUV) Aerosol Mass Spectrometry
We use VUV aerosol mass spectrometry to measure the change in chemical composition of an aerosol undergoing a heterogeneous reaction. This allows us to measure reaction product distributions and heterogeneous kinetics, required for developing detailed reaction mechanisms.
Atmospheric Pressure Mass Spectrometry
We have adapted a number of commercial ionization sources (DART and ESI) to measure real time nanoparticle and droplet chemistry. These ionization source are coupled to a Thermofisher Orbitrap and Velos Pro mass spectrometer for high resolution mass analysis.
Stochastic Reaction Diffusion Simulations
In collaboration with Dr. Frances Houle (LBNL) we use reaction diffusion simulations to model experimental heterogeneous kinetics, which affords deeper insight into molecular reaction mechanisms at droplet and aerosol interfaces. We use the open access software program, Kinetiscope, developed by William Hinsberg and Frances Houle.