Observation of electron bubbles in para-H-2-D-2 (HD) mixtures by high-resolution ESR spectroscopy

A sharp singlet signal assigned to electron bubbles was observed in gamma-i rradiated solid para-H-2-D-2 (HD) mixtures by use of high-resolution ESR sp ectroscopy. The signal was not observed in pure para-H-2 but in the mixture s. This result indicates that the D-2 and HD molecules play an important ro le in the formation of the electron bubbles in para-H-2. The electron bubbl es decay with a half-lifetime of about 2 h, and the decay rate constant at 4.2 K is very close to that at 2.2 K. This result shows that the electron b ubbles migrate in the p-H-2 sample via quantum mechanical tunneling.