Electron Impact Excitation of Potassium and Sodium.

Absolute electron-impact optical excitation functions of 24. transitions of the sharp, principal, diffuse, and fundamental series. of potassium have been measured in the impact energy range. 0-400 eV. The determination of the target atom number density. was made by measuring the transmission of potassium resonance. radiation from a fluorescence cell upon passage through the. collision chamber. Direct excitation cross sections of 14 states (5S,6S,7S,8S,4P,5P,6P,7P,3D,5D,6D,5F,6F, and 7F) have been determined from the measured optical excitation cross sections with the aid of radiative transition probabilities taken from the literature. These direct cross section results are compared with theoretical calculations based upon the Born approximation and the multi-state close-coupling approximation. Measurements were also made of the polarization of resolved components of the 4P-4S and 3D-4P doublets, and from these results the direct excitation functions of the separate orbital magnetic substates of the 3P state have been determined. This work has been extended to sodium, yielding measurements of optical excitation functions of 26 transitions of the sharp, principal, diffuse, fundamental, and nP-4S series in the energy range 0-150 eV. From these measurements, direct excitation functions of 14 states (4S,5S,6S,7S,3P,4P,5P,6P,3D,4D,5D,6D,6F, and 7F) have been determined. These are compared with theoretical results based on the Born approximation and the close-coupling method. Polarization measurements were made for several sharp, principal, and diffuse doublets, and this data is applied to determine the magnetic substate direct excitation functions for the 3P state.