Analysis of (1, 2) (1, 3) and (2, 3) Bands in the c³II_u-b³II_g System of P₂

We investigate the high resolution absorption spectroscopy of P₂ radical, generated in ac glow discharge of PCl₃ buffered with helium, using optical heterodyne magnetic rotation enhanced concentration modulation spectroscopy in the visible region. The (1, 2), (1, 3) and (2, 3) bands of c³II_u-b³II_g in the range 16620--17860cm^-1 are observed and their ³II₂-³II₂ subbands are rotationally analysed. A set of effective molecular constants for the Ω=2 component of the states　involved are determined.