Broadening of the Potassium Resonance Lines for High Pressures of a Homogenous Absorbing Vapor

The shapes of the potassium resonance lines were obtained by a direct contour method. The pressures of the homogeneous absorbing vapor ranged from .001 to 20 mm Hg. The absorption coefficient was inversely proportional to the square of the distance from the line center. The half-breadths: varied linearly with the density of the absorbing atoms; were independent of the (relative) f-value of each line; yielded a Lorentz optical collision diameter of 200A. No asymmetries or shifts were detected. The experiment was made possible by the use of the new corrosion-resistant MgO windows.