Pressure Effects of Hydrogen and Nitrogen on the Second Doublet of Rb Principal Series

Pressure effects of nitrogen and hydrogen on the second doublet of the rubidium principal series, were studied at pressures up to 13 atmospheres. Both for hydrogen and nitrogen the ${}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ component broadens more conspicuously than the ${}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ one, and the relationship between the half-width and the relative density is linear. Nitrogen produces a red shift for both components, while hydrogen has a weaker red shift for ${}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ and a stronger violet shift for ${}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$. The departure from a linear relationship between shift and the density of the perturbing gases is quite manifest. Study of the line contours reveals marked asymmetry, toward the red in the case of nitrogen and slightly toward the blue for hydrogen. The relationship between the half-width and the shift is discussed.