High-resolution analysis of the v1 and v5 bands of phosgene 35Cl2CO and 35Cl37ClCO

Fourier transform spectra of phosgene (Cl2CO) have been recorded in the 11.75 and 5.47 m spectral regions using a Bruker IFS125HR spectrometer at resolutions of 0.00102 and 0.0015 cm(-1), respectively, leading to the observation of the (5) and (1) vibrational bands of the two isotopologues (Cl2CO)-Cl-35 and (ClClCO)-Cl-35-Cl-37. The corresponding upper state ro-vibrational levels were fit using Watson-type Hamiltonians and/or a Hamiltonian matrix accounting for resonance effects when necessary. In this way, it was possible to reproduce the upper state ro-vibrational levels to within the experimental accuracy, i.e. approximate to 0.17 x 10(-3) cm(-1). Very accurate rotational and centrifugal distortion constants were derived from the fit together with the following band centres: (0)((5,) (Cl2CO)-Cl-35) = 851.012737(20) cm(-1), (0)((5,) (ClClCO)-Cl-35-Cl-37) = 849.995451(90) cm(-1), (0)((2 +) (3,) (ClClCO)-Cl-35-Cl-37) = 864.42370(50) cm(-1), (0)((1,) (Cl2CO)-Cl-35) = 1828.202514(40) cm(-1) and (0)((1,) (ClClCO)-Cl-35-Cl-37) = 1827.246444(20) cm(-1).