The ultraviolet band systemsA¹Π-X¹Σ⁺ of P¹⁴N and P¹⁵N were excited in an electrodeless tube containing traces of phosphorus specpure nitrogen and neon using a microwave discharge (2450 MHz). Bands of the isotopic species, P¹⁵N, were obtained using¹⁵N₂ enriched to 95.5%. Rotational analyses of eleven bands of P¹⁴N and sixteen bands of P¹⁵N were carried out. Three perturbing statese³Σ⁻,d³Δ andb³Π, arising from the lower valence configurations were identified from the observed perturbations in thev′=0–4 levels of theA¹Π state. Deperturbation studies led to the determination of molecular constants of the perturbing states. Vibrational assignments of the perturbing states were made from isotope shift studies.