The v 3 band of 14 C 16 O 2 molecule measured by optical-frequency-comb-assisted cavity ring-down spectroscopy

The infrared spectrum of the rare isotopologue 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 ν3 fundamental band have been detected. Their absolute frequency was measured with a relative uncertainty ranging from to . 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.