HYDROGEN UPTAKE EFFECTS ON STRUCTURES AND SOLID-STATE PROPERTIES IN K3C60

Charge transfer complexes of polycyclic aromatic hydrocarbons with alk ali metal are known to adsorb hydrogen chemisorptively. We investigate hydrogen uptake effects on the properties of metallic K3C60 by means of ESR and superconductivity measurements. The introduction of hydroge n induces a disproportionation reaction, resulting in the generation o f K6C60 domains which have interstitial sites available for the accomm odation of dissociated hydrogen atoms. The annealing process makes the hydrogenated K3C60 homogeneous where small amounts of hydrogen are st abilized as impurities. Superconductivity is not influenced by hydroge n uptake.