The spectral dependence of the photodetachment cross section for the negative ion of atomic hydrogen has been measured in the range from 4000 A to 13 000 A with approximately 300-A resolution. Measurements were made with twenty-five band pass filters, each measurement taken relative to the value obtained with a control filter at 5280 A. A probable error of about 2% is attached to the relative value obtained for each filter. The results are in significant disagreement with available calculated cross sections.

• Received 13 July 1959

DOI:https://doi.org/10.1103/PhysRev.116.1125