The ?1+ 5?3Dyad of12CO2and13CO2

Abstract The (1 0 0 5) 1,2 → (1 0 0 4) 1,2 and (1 0 0 6) 1,2 → (1 0 0 5) 1,2 emission bands of 12 C 16 O 2 have been recorded near 4.5 μm by Fourier transform spectroscopy of a CO 2 + N 2 mixture excited by dc discharge. The spectroscopic parameters of the (1 0 0 v 3 ) 1,2 vibrational states with v 3 = 0–6 have been obtained from a global rotational analysis of the six (1 0 0 v 3 ) 1,2 → (1 0 0 ( v 3 –1)) 1,2 emission bands ( v 3 = 1–6). The (1 0 0 5) 1,2 vibrational states of both 12 C 16 O 2 and 13 C 16 O 2 have been observed by direct absorption from the vibrational ground state by Intracavity Laser Absorption Spectroscopy near 12 700 and 12 400 cm −1 , respectively. The rovibrational energy levels obtained by the two experimental techniques are discussed and compared with those calculated in the framework of the effective operator approach.

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