A combined experimental and computational study on the ionization energies of the cyclic and linear C3H isomers.

For the first time, two hydrogen-deficient hydrocarbon radicals are generated in situ via laser ablation of graphite and seeding the ablated species in acetylene gas, which acts as a carrier and reactant simultaneously. By recording photoionization efficiency curves (PIE) and simulating the experimental spectrum with computed Franck-Condon (FC) factors, we can reproduce the general pattern of the PIE curve of m/z=37. We recover ionization energies of 9.15 eV and 9.76 eV for the linear and cyclic isomers, respectively. Our combined experimental and theoretical studies provide an unprecedented, versatile pathway to investigate the ionization energies of even more complex hydrocarbon radicals in situ, which are difficult to prepare by classical synthesis, in future experiments.