Cold, Ion-Neutral, Chemical Reactions in Coulomb Crystals
ORAL · Invited
Abstract
Laser-cooled ions in radio frequency traps can form Coulomb crystals, which are a unique environment in which to study ion-neutral, gas-phase reaction kinetics and dynamics. The low pressures and cold conditions offered by this environment mimic important aspects of the astrochemical environment. This expands the relevance of our cold chemistry studies to dynamics throughout multiple regions of space, including the interstellar medium and planetary atmospheres. Three important reactions of interstellar interest were studied within a Coulomb crystal environment: CCl+ + CH3CN, CCl+ + C6H6, and C2H2+ + CH3CN. Each of these reactions demonstrated products of interest to astrochemical modelers and complementary computational work revealed insights into the reaction mechanisms. My dissertation also included preparation for the next phase of this experiment by integrating a traveling wave Stark decelerator (TWSD) as a neutral molecular beam source to the ion trap; this allows future reactions in our linear ion trap to be energy-resolved over the collision "temperature'' range of ~1-50 K. This combined setup broadens the astrochemical relevance of our measurements and provides an excellent opportunity to understand the underlying impacts of collision energy on reaction dynamics.
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Publication: O. A. Krohn, K. J. Catani, J. Greenberg, S. P. Sundar, G. da Silva and H. J. Lewandowski. "Isotope-specifi<br>reactions of acetonitrile (CH3CN) with trapped, translationally cold CCl+." J. Chem. Phys. 154, 074305 <br>(2021).<br>O. A. Krohn, K.J. Catani, H. J. Lewandowski "Formation of astrochemical relevant molecular ions: Reaction of <br>translationally cold CCl+ with benzene in a linear ion trap." Phys Rev. A. 105 (2) L020801. (2022) <br>O. A. Krohn, K. J. Catani, S. P. Sundar, J. Greenberg, G. da Silva and H. J. Lewandowski. "Reactions of <br>Acetonitrile with Trapped, Translationally Cold Acetylene Cations." J. Phys. Chem. A. 127 (24), 5120-5128 <br>(2023) <br>J. Greenberg, O. A. Krohn, Jason A. Bossert, Yomay Shyur, David Macaluso, N. J. Fitch, H. J. Lewandowski. <br>"Velocity-tunable beam of continuously decelerated polar molecules for ion-molecule reaction studies." Rev. <br>Sci. Instr. 92 (10) 103202. (2021) <br>O. A. Krohn and H. J. Lewandowski. "Cold ion-molecule reactions in the extreme environment of a Coulomb <br>crystal." J. Phys. Chem. A. 128, 10, 1737–1752. (2024)
