We have designed a pulsed discharge nozzle which passes a high voltage discharge between two electr
odes that ionizes a buffer gas (typically Ar) through Penning Ionization. The ionized Ar will then initiate chemical reaction of the dilute chemical species seeded into the buffer gas. Since these radicals are highly reactive, they combine with other radicals to create exotic chemical species that are difficult to make through bench-top synthesis.
By monitoring the rotational spectrum, we can detect the different products species that are formed. In fact, if all of the products have dipole moments, we can detect ALL of the products that are formed at once, including isomers and conformers. This will give us information about the reaction surface that the radical species travel on their way to products.
Here is a spectrum taken with 2,3-Dihydrofuran (DHF) at -800 V and +300 V on the discharge nozzle. The top spectrum shows the actual data taken with our discharge setup. The bottom spectrum shows the predicted spectra for each of the different compounds that are formed from the combustion of DHF. The fitted products were taken from predicted lists.1
1. A. Lifshitz, M. Bidani J. Phys. Chem. 93 (1989) 1139-1144.