Rotational Analysis of the ₃A Bands of CO

Abstract

THE so-called 3A bands of CO in the region 2200–2600 A. have been excited with high intensity in a discharge through neon in a Geissler tube with carbon electrodes, and the (0,1), (0,2) and (0,3) bands at 2389, 2489 and 2596 A. have been photographed in the first order of a large Hochheimized concave grating (dispersion 1.3 A./mm.). By fine-structure analysis twelve branches have been detected in each band, the others being weak and overlapped. Of these twelve branches, six form heads, namely, O₃, o₂, P₃, P₂, P₁, Q₁ in order of diminishing wavelengths, and six do not form heads, namely, R₃, R₂, R₁, Q₃, Q₂, S₁. This shows the upper state to be a 3 state, the rotational constant of which is found to be 1.9563 cm.¹ from the average of three times six double combinations for the upper state.