Exploring photoionization of gas-phase free radicals with a widely tunable VUV laser at moderate spectral resolution.

The VUv Laser for Considering Astrophysical and Isolated Molecules (VULCAIMs) setup [Harper et al., Phys. Chem.

The isomer distribution of CH products from the propargyl radical gas-phase recombination investigated by threshold-photoelectron spectroscopy.

The resonance-stabilization of the propargyl radical (CH) makes it among the most important reactive intermediates in extreme environments and grants it a long enough lifetime to recombine in both terrestrial combustion media and cold molecular clouds in space. This makes the propargyl self-reaction a pivotal step in the formation of benzene, the first aromatic ring, to eventually lead to polycyclic aromatic hydrocarbons in a variety of environments. In this work, by producing propargyl radicals in a flow tube where propyne reacted with F atoms and probing the reaction products by mass-selected threshold-photoelectron spectroscopy (TPES), we identified eight CH products in total, including benzene.

Photoelectron spectrum of the pyridyl radical.

We report the photoelectron spectrum of the pyridyl radical (CHN), a species of interest in astrochemistry and combustion. The radicals were produced hydrogen abstraction in a fluorine discharge and ionized with synchrotron radiation. Mass-selected slow photoelectron spectra of the products were obtained from photoelectron-photoion coincidence spectra.