ESR and X-ray investigations of deuterium atoms and molecules in impurity-helium solids

Impurity-helium solids created by injecting deuterium atoms and molecules into superfluid 4He have been studied via electron spin resonance (ESR) and x-ray diffraction methods. We measured the g-factor, the hyperfine constant and the spin-lattice relaxation time of D atoms in D-D2-He solids. These measurements show that D atoms are mainly stabilized in D2 clusters. Using an x-ray method we found the size of D2 clusters to be ∼90A in diameter and the densities of D2 molecules in the samples to be of order 2.5⋅1021 cm−3 . The highest average concentration of D atoms achieved in D-D2-He solids was ∼1.5⋅1018 cm−3 . The local concentrations of D atoms within D2 clusters is found to be large (∼2⋅1019 cm−3).