Equilibrium structure and anharmonic potential function of phosgene: Diode laser spectra of the ν1 and ν5 bands

The vibration-rotation spectra of the ν₁ and ν₅ bands of phosgene ( ³⁵Cl ₂CO) were measured and analyzed with the aid of Stark modulation spectra for assignment of complicated spectral features. The rotational constants for the ν₁ state were determined to be A₁ = 7885.65(17), B₁ = 3470.25(9), and C₁ = 2406.85(9) MHz. They were used with the ones for the ν₂ ∼ ν₆ states reported previously for derivation of the equilibrium rotational constants of ³⁵Cl ₂CO: A_e = 7950.35(22), B_e = 3490.22(11), and C_e = 2425.44(22) MHz.