Electronic absorption spectra of C4− and C6− chains in neon matrices

The absorption spectra of the electronic transitions A 2Σg+←X 2Πg, B 2Σu+←X 2Πg, (2) 2Πu←X 2Πg, and (3) 2Πu←X 2Πg of C4−, as well as A 2Σg+←X 2Πu, (2) 2Πg←X 2Πu, and (3) 2Πg←X 2Πu of C6− have been obtained in neon matrices. The spectra were measured after mass-selected deposition of the anions with excess of neon at 5 K. The assignments are based on mass-selection, spectroscopic evidence, photobleaching behavior, and ab initio calculations. Vibrational frequencies in the electronically excited states have been inferred.