The ultraviolet bands ofA¹Π-X¹Σ⁺ system of As¹⁴N and its isotopic species As¹⁵N were excited in a quartz tube containing specpure nitrogen and traces of AsCl₃ vapour, using a microwave discharge (2450 MHz). Bands of As¹⁵N were obtained using¹⁵N₂ enriched to 95.5%. Rotational structure of several bands of As¹⁴N and As¹⁵N photographed under high dispersion (0.14 Å/mm) was reanalysed. Detailed studies of the observed perturbations in the levels ofν′ = 0 to 4 led to the identification of two³Σ⁻ and aC¹Σ⁻ states. Molecular parametersT_e, ω_e, ω_ex_e, B_eandα_ewere determined for all the electronic states studied. Vibrational assignments of the perturbing levels were made using the isotope shift studies.