Electronic and Infrared Spectra of HC2nO (n = 3-7) Chains.

Abstract

Electronic and infrared spectra of HC2nO+ (n = 3-7) chains contained in a cryogenically cooled ion trap are measured using resonance-enhanced photodissociation spectroscopy. The HC2nO+ chains, which possess X̃3Σ- ground electronic states, are prepared through spin-forbidden association reactions between HC2n-1+ chains and CO molecules, both of which have X̃1Σ+ ground states. Infrared spectra of N2-tagged HC2nO+ (n = 4-7) chains measured over the 550-1820 cm-1 range exhibit weak bands associated with chain stretch and bend vibrational modes, with more intense C≡C and CO stretch bands predicted to occur in the 2200-2300 cm-1 region. Electronic spectra of bare HC2nO+ (n = 3-6) chains measured o..