Experimental Evidence for Radiative Attachment in Astrochemistry from Electron Attachment to Nccccn

Electron attachment to NCCCCN, dicyanoacetylene (2-butynedinitrile), has been observed. Metastable parent anions, NCCCCN , with microsecond or longer lifetimes are formed close to 0 eV electron energy with a cross ∗ section of ≥0.25 . The stability of NCCCCN suggests that radiative attachment to NCCCCN and similar ∗ Å linear carbon chain molecules may be an important mechanism for the formation of negatively charged molecular ions in astrophysical environments. CCCN and CN fragment anions are formed at ∼3 and ∼6 eV. Subject headings: astrochemistry — ISM: molecules — molecular processes