Hydrogen shows no measurable backscattering for photoelectrons in extended x-ray absorption fine structure. When a H atom is located between an absorber and a backscatterer, however, it affects the photoelectron wave in magnitude and phase. This is demonstrated on Ni and Cr hydrides. The radial and angular information of the hydrogen position provided by this effect has a wide range of applicabilities such as the structure of metal-hydrogen systems, the trapping of hydrogen by impurities, and the determination of hydrogen bonds in molecules.

• Received 19 March 1984

DOI:https://doi.org/10.1103/PhysRevLett.53.74