Ultra-Violet Bands of Oxide of Phosphorus

Abstract

THE Phosphorus arc in air gives out a band spectrum in the ultra-violet, which is attributed to the PO molecule. The vibrational quantum analysis of these bands has been previously done by one of the authors¹. The rotational structure analysis of the (0,0) band at λ2477.80 shows that it consists of six main branches, namely, P₁ Q₁ R₁ and P₂ Q₂ R₂ and two other faint satellite branches. For low quantum numbers, the satellite branches RQ₂₁, QP₂₁, PQ₁₂ and QR₁₂ are superposed on the main branches. The intensity of the lines of the different branches satisfy the criterion of a ^{2 2} transition. The band structure is analogous to the bands of NO₁ as is anticipated from theoretical considerations. The following molecular constants (cm¹ units) have been obtained.