A high resolution study of A1Π–X1Σ transition of the PN molecule

Abstract

The emission spectrum of PN has been rephotographed at high resolution in the spectral region 2200 to 3100 Å. The bands analyzed involve ν′ = 0–10 to ν″ = 0–11 transitions of the A1Π–X1Σ+ system of which only a few of the strongest bands have previously been reported at low and medium resolution. From a rotational analysis of the spectrum, new perturbations in the ν′ = 0, 2, 3, and 7 levels of they'll have been observed. A deperturbation study of these levels as well as a previously reported perturbation in the ν′ = 1 identify the perturbing states as 3Δ perturbing A1Π, ν = 0 and 3Σ− perturbing A1Π, ν = 2 and 3; both states arising from the 1π42π37σ23π configuration. Molecular constants for the perturbing states are obtained in addition to improved molecular constants for the A1Π state.