The Zeeman Effect in the Red CaH Bands

The Zeeman effect in the red ²Π→²Σ and ²Σ→²Σ CaH bands, together with new satellite branches in the ²Π→²Σ system, are reported. Field strengths up to 30,000 gauss were employed, the dispersion of the large concave grating in a parallel light mounting being about 2.1A per mm.Satellite series in the ²Π→²Σ bands.---The ⁰P₁₂ satellite branches are measured for both the A and A^' bands. These frequencies together with certain combination relations fix the hitherto uncertain J numbering in the Q branches, and hence the size of the Λ-type doubling. This doubling is very large (70 cm^-1 at K=341/2) and of opposite sign to that usually found in other bands.Zeeman effect in the ²Π→²Σ bands.---General agreement with the pattern blocks predicted by Hill's theoretical formulas for the lower K^' states is found. I ntensity variations with increasing field strength are described. For K^'>19, where the no-field spin doublet components come together and cross over, uncoupling effects occur. Only the transitions from anti-parallel S and K in the ²Π state to parallel S and H in the ²Σ state, and from parallel S and K to antiparallel S and H persist. The displacements of these components are proportional to H². At 30,000 gauss the high K components in the P₁ branch broaden out and go rapidly to zero intensity, but the P₂ field components remain narrow and strong. With complete uncoupling by this "strong field," these components are probably the transitions from parallel S and H in the ²Π state to parallel S and H in the ²Σ state. For the highest K levels, these high-field P₂ components are displaced farther from the no-field position and become more diffuse, suggestive of an approach to Hund's case d.Zeeman effect in the ²Σ→²Σ bands.---Contrary to the usual findings for bands of this type, broad and prominent Zeeman patterns here occur for K^'>8 which are quite similar to those found in a ²Π state. The explanation is probably that an appreciable magnetic moment is created in the upper 4sσ²3dσ²Σ state by the increasing component of L along the rotational axis.