The ~1#PI#_u <- X ~1#SIGMA#_g~+ electronic spectrum of C_5 in the gas phase

摘要

The origin and three vibronic bands of the ~1#PI#_u <- X ~1#SIGMA#_g~+ electronic transition of linear C_5 have been observed in the gas phase. The carbon chain is produced in a slit nozzle employing both discharge and ablation techniques. Cavity ring down spectroscopy is used to measure the electronic transition. The origin band is found at 510.94(1) nm, shifted 29 cm~(-1) to the red of the value in a neon matrix. Intramolecular processes lead to broadening and irregularities in the rotational structure. The relation to astronomical observations is discussed.