B2Σu+←X2Πg electronic spectrum of NCCN+ in the gas phase

The B-2 Sigma(+)(u)<- X-2 Pi(g) absorption spectrum of NCCN+ in the gas-phase was observed using a two-color, two-photon photodissociation technique. This was measured at similar to 20 K in a 22-pole ion trap with laser bandwidths of less than a cm(-1). The spectrum shows distinct vibrational structure, with the origin band near 11 253 cm(-1), and the excitation of four normal modes in the excited state. The rotational structure of the 0(0)(0) band in the gas phase could not be resolved, indicating that the B-2 Sigma(+)(u) state has a lifetime of a few picoseconds because of a fast intramolecular process. (C) 2008 American Institute of Physics.