ABSOLUTE TRIPLY DIFFERENTIAL (E,2E) CROSS-SECTION MEASUREMENTS FOR H WITH COMPARISON TO THEORY

Absolute triply differential (e,2e) cross section measurements are pre sented for H (for incident energies, E-0, of 15.6 and 17.6 eV) for equ al energy sharing and the theta(12) = pi configuration. Results of dis torted partial wave calculations agree with the measurements; those of convergent close coupling calculations agree with the relative angula r distributions, but are lower than experiment by factors of from 2 to 7. Relative experimental results for H for E-0 = 14.6 eV show a quali tative change in shape, which agrees with theory. Implications of the absolute experimental results for the range of validity of the Wannier threshold law are discussed.