High-resolution photoelectron imaging of cryogenically cooled α- and β-furanyl anions

Isomer-specific, high-resolution photoelectron spectra of α- and β-furanyl obtained via slow electron velocity-map imaging of cryogenically cooled anions are reported. The spectra yield electron affinities of 1.8546(4) and 1.6566(4) eV for the α- and β-furanyl neutral radicals, respectively. New vibronic structure is resolved and assigned based on density functional theory and Franck-Condon simulations, providing several vibrational frequencies for the ground electronic state of both neutral isomers. Subtle differences in orbital hybridization resulting from varying proximity of the deprotonated carbon to the heteroatom are inferred from photoelectron angular distributions, and the C_β[sbnd]H bond dissociation energy is estimated from a combination of experimental and theoretical results to be 119.9(2) kcal mol⁻¹.