Vibrationally resolved spectra of C2–C11 by anion photoelectron spectroscopy

Abstract
Anion photoelectron spectroscopy has been employed to obtain vibrationally resolved spectra of the carbon molecules C2–C11. The spectra of C2–C9 are dominated by linear anion to linear neutral photodetachment transitions. Linear to linear transitions contribute to the C11 spectrum, as well. From these spectra, vibrational frequencies and electron affinities are determined for the linear isomers of C2–C9 and C11. The term value is also obtained for the first excited electronic state of linear C4. The spectra of C10 and C11 show evidence for transitions involving cyclic anions and/or neutrals. Similar types of transitions are identified in the spectra of other smaller molecules, specifically C6, C8, and to a lesser extent C5.