Hydrogen and deuterium atoms, stabilized by condensation of an atomic beam in superfluid helium

Concentrations of H and D atoms, stabilized in a molecular matrix, up to 1 x 10/sup 20/ cm/sup -3/ are achieved by condensation of an atomic beam in superfluid helium. Transformation of D atoms into H atoms is observed, indicating the occurrence of tunneling chemical exchange reactions between atomic and molecular hydrogen isotopes.