O(1D) Insertion Reactions
Many of the molecules formed in the first steps of prebiotic astrochemistry are transient species and therefore present experimental challenges. Some of these species have been observed in the laboratory as the products of O(1D) insertion reactions in rare gas matrices. We plan to use this highly exothermic process to produce transient molecules of importance in prebiotic astrochemistry:
The requirement for a gas-phase production mechanism leads to difficulty with these experiments. The products tend to undergo unimolecular decomposition because the insertion reactions are so exothermic. Additionally, any production mechanism for O(1D) will also destroy the organic precursor molecules. To circumvent these problems, we are developing a new supersonic photolysis fast-mixing nozzle that allows on-the-fly production and reaction of O(1D) with organic precursors:
In this design, the O(1D) is produced in a separate photolysis region before injection of the organic precursor. The O(1D) then mixes with the organic precursor, insertion occurs, and the subsequent supersonic expansion quenches the excess vibrational energy of the product. This leads to longer molecular lifetimes and allows spectroscopic studies to be performed. The insertion can be optimized by varying the length of the interaction region. This approach can also be used for kinetic studies of the insertion mechanism.