Raman and infrared spectra of gaseous and solid nitrosyl chloride

Abstract The Raman spectra of gaseous and solid nitrosyl chloride, ONCl, have been recorded from 10 to 2200 cm −1 . In the spectrum of the gas, the three fundamentals for the isotopic species ON 35 Cl were observed at: ν 1 = 1799.7, ν 2 = 595.7, and ν 3 = 331.8 cm −1 . Large shifts from these frequencies were observed for the solid material. The infrared spectra of the gaseous and solid nitrosyl chloride were recorded from 30 to 2000 cm −1 . The spectrum of the gas was recorded at a resolution of 0.06 cm −1 and the vibrational-rotational structure for both ν 2 and ν 3 was analyzed in the ground and excited vibrational states. Band origins were determined to be at 595.860(3) and 331.973(4) cm −1 for ν 2 and ν 3 , respectively, for ON 35 Cl and the corresponding band centers for ON 37 Cl were approximately 594.9 and 328.2 cm −1 . The pure rotational infrared spectrum of ONCl was recorded (20 to 120 cm −1 ) and interpreted in terms of a slightly asymmetric prolate top with centrifugal distortion. Series of 17 and 10 sharp Q branches were observed for the ON 35 Cl ground state and v 3 = 1 excited state, respectively. A new force field based on new and existing data is proposed and discussed.