ESR and X-ray Investigations of Deuterium Atoms and Molecules in Impurity-Helium Solids

Abstract

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 ∼90Å 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).