Electron Transmission Spectroscopy in Atomic Hydrogen

An electron transmission experiment is used to study the resonances in the total scattering cross section of atomic hydrogen below the threshold of the first excited state. The three lowest resonances, designated ${}_{}{}^1{}_{}{}^{}S$, ${}_{}{}^3{}_{}{}^{}P$, and ${}_{}{}^1{}_{}{}^{}D$, are observed and their energies and decay widths are found to be in good agreement with the values predicted theoretically using close coupling with correlation.