Vibrational Spectra and Force Constants for Isotopic Species of Nitrosyl Chloride

From infrared absorption studies in the gaseous phase, fundamental harmonic vibrational frequencies have been determined for 16O14N35Cl, 16O15N35Cl, 18O14N35Cl, and 18O15N35Cl. With the aid of centrifugal-distortion data from the literature, a unique general quadratic valence-force-constant solution was obtained. The resulting values are: FNO = 15.26 mdyn Å−1, FNCl = 1.27 mdyn Å−1, Fα = 1.32 mdyn Å−1·rad−2, FNO,NCl = 1.53 mdyn Å−1, FNO,α = 0.1 mdyn rad−1, FNCl,α = 0.12 mdyn rad−1.