New band systems were found in the spectra of AsO and PO molecules excited by short-wave oscillations. The new bands of AsO arise from a transition A′2∏i(a) → X2∏r, and their band heads can be arranged in a system given by the formula: ν = [equation]. Two new systems F → B and G → B were identified in the spectrum of PO. The term values of the F and G states are about 55585 and 56358 cm-1. New bands were found in the known D → B system which lead to the following constants for the D state Te=[equation] and ωe′≅755 cm-1.
S. MROZOWSKI and C. SANTARAM, "Electronic Spectra of AsO and PO: New Band Systems in the Visible," J. Opt. Soc. Am. 56, 1174-1178 (1966)