The absorption spectrum of solid oxygen in the wavelength region from 12,000 Å to 3300 Å

Abstract

The electronic absorption band systems of oxygen with upper states 1 Δ g , 1 Σ g + , 1 Δ g + 1 Δ g , 1 Δ g + 1 Σ g + and 1 Σ g + 1 Σ g + were investigated in detail in the a form of the solid (~21°K); some data were obtained also for the β and γ modifications. Although the nineteen bands of α-O 2 studied exhibit great diversity in structure, the profiles show in general a rather sharp red edge and intensity degradation towards the violet. The over-all structure of each band is interpreted as the superposition of combination tones of the appropriate molecular frequency v m with continuous distributions of lattice frequencies; each distribution is more or less sharply peaked at v = v m + nv D ( n = 0, 1, 2, ⋯), where v D is the Debye frequency of the solid. The main component of the 0-0 band of each system corresponds to double phonon creation ( n = 2); for the higher members of each vibrational progression, single phonon creation ( n = 1) is more probable. Most of the subsidiary maxima correspond to less probable phonon transitions, i.e. with n not equal to the most probable value. The molecular constants ( T e' , ω e' , x e' , ω e' ) derived from the analysis depart very little from the values for the free molecule.