2007ApJ...655L..57G

The rotational spectra of the butadiyne anion C₄H^– and the octatetrayne anion C₈H^– have been detected in the laboratory. Precise spectroscopic constants for these closed-shell molecules have been obtained, which enable their rotational spectra to be calculated to high accuracy throughout the radio band. Deep astronomical searches can now be undertaken in essentially any molecular source, including TMC-1 and IRC +10216, where the negative ion C₆H^– has recently been detected. The large dipole moments and high binding energies of both anions make them good candidates for astronomical detection.