Leah Dodson

Many of the new molecules discovered in astrophysical objects are totally outlandish by traditional perspectives: long linear unsaturated carbon chains, metals in surprising charge states, and strained ring structures have all challenged chemists to think beyond terrestrial conventions in explaining how these molecules form and react, and where they fit into the overall cycle of planetary and stellar evolution. The challenge to the community is to study this exotic chemistry under the relevant physical conditions—most importantly the low temperatures of space. In this talk, I will describe two orthogonal research projects occurring in our group that are unified by their study of the fundamental physical processes that impact low-temperature (down to 10 K) experiments.

In the first part of my talk, I will share recent results from our study of porous materials—such as metal-organic and covalent-organic frameworks—at temperatures down to 30 K. Using our cryogenic spectroscopy tools, we are now investigating the preparation of small molecules in specific quantum states enabled by these low temperatures. State-selective preparation of molecules such as H2, H2O, and CH4 in their lowest-energy nuclear-spin states will open doors in many fields, including the evolution of comets in our solar system.

In the second part of my talk, I will describe our investigation of the photodissociation of methanol by ultraviolet photons, a subject of interest to the astronomy community. This work is carried out at the Advanced Light Source user facility in Berkeley, CA in collaboration with scientists at Sandia National Labs using their Multiplexed Photoionization Mass Spectrometer to directly detect reactants, intermediates, and products in the reaction system. Methanol photodissociation products were measured quantitatively, enabling the determination of absolute photolysis yields, while also revealing new insights into unique product channels, including the novel detection of a reactive carbene species.

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