Electronic Absorption Spectra of Carbon Chain Anions (n = 2−5) in Neon Matrices

Absorption spectra showing transitions to several excited electronic states of ( n = 2−5) chains were observed. The spectra were recorded after codeposition of mass-selected anions with neon to form a matrix at 5 K. The assignment follows from mass-selection, the monotonic dependence of the wavelength of the electronic origin band on the number of carbon atoms, photobleaching changes, and spectroscopic considerations. The absorption band systems can be attributed to 2 Π ← X 2 Π transitions. For two transitions are observed, for three, and for and four.