Further Studies in the Spectrum of the OH Molecule: A New (2,2) Band; Satellite Series inλ3122;Λ-Type Doubling and Electronic Spin Doubling

The investigations begun in the neighborhood of the (0′,1″) band at $\lambda 3428$ (cf. [3]) have been extended to include the bands of the (0,0) and (1′,0″) sequences. Approximately 400 lines were observed in this region of the spectrum, of which 120 are reported for the first time. All but 18 of these have been successfully assigned. The assignments include the identification of a new (2,2) band with its principal head at $\lambda 3185$; the identification of ${}_{}{}^{\mathrm{RR}}{}_{}{}^{}R_{21}^{}{}_{}{}^{}$ and of ${}_{}{}^{\mathrm{PP}}{}_{}{}^{}P_{12}^{}{}_{}{}^{}$ satellite branches of the (1,1) band; complete assignments of the regular $R$-branches of the (1,1) and (2′,1″) bands; and extensions of nearly all the remaining branches of the bands which appear in this region. The new data are also utilized to obtain $\Lambda$-doublets and spin doublets to $K=35\mathrm{}$ for the 0″ level and to somewhat smaller values of $K$ for the 1″ and 2″ levels. The experimental results are compared with equations in the literature. Molecular constants derived from the new (2,2) band are in good agreement with those derived from the (1′,2″) band.