The ν3 band of 14C16O2 molecule measured by optical-frequency-comb-assisted cavity ring-down spectroscopy

The infrared spectrum of the rare isotopologue (CO2)-C-14-O-16 has been investigated in the range 2190-2250 cm(-1) with a frequency-comb-referenced cavity ring-down spectrometer. Thirty-three ro-vibrational transitions of the nu(3) fundamental band have been detected. Their absolute frequency was measured with a relative uncertainty ranging from 7.1 x 10(-8) to 1.1 x 10(-8). The experimental frequencies were fitted to the conventional Hamiltonian of a linear molecule and a new set of spectroscopic parameters for the fundamental vibrational state has been improved for this species.