Infrared laser spectrum and structure of phosphoryl chloride (CIPO) formed at ambient temperature in the gas phase

The infrared spectrum of the transient molecule phosphoryl chloride (ClPO) has been measured in the gas phase at room temperature using infrared diode laser absorption spectroscopy around 8 mu m. The molecule was generated in a flow system either by adding molecular chlorine to a mixture of white phosphorus vapor and oxygen or by reacting atomic oxygen with phosphorus trichloride vapor. The infrared spectrum arises from the P-O stretching fundamental (nu(1)) of ClPO. The band origin is determined as 1263.007 00(22) cm(-1), which is 5 cm(-1) higher than the Ar matrix value and nearly 10 cm(-1) lower than a recent low-resolution gas phase FTIR measurement. The rotational constants derived from the diode laser experiment, A = 1.120, B = 0.151429(29), and C = 0.133 236(23) cm(-1), are very close to those calculated from the density functional theory (B3LYP) structure of RCl-P = 2.0958 Angstrom, RP-O = 1.4650 Angstrom, and angle Cl-P-O = 110.07 degrees.