ISOTOPE EFFECTS IN THE 77 K GAMMA-IRRADIATION OF ICE.
Rept. for 1 Oct 65-5 Aug 66,
AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
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The radiation yields of H2, D2, and HD obtained by the 77 K gamma-irradiation of solute free mixed H2O and D2O ice mixtures have been determined by use of mass spectroscopy. The total gas yields have been determined, too, both by use of a calibrated mass spectrometer and by manometric methods. Significant isotope effects were observed over a wide range of isotopic compositions studied i.e., the deuterium content varied from 0.016 to 99.8. The separation factor alpha G HDgasHDice varied from ca 70 for the high D content ice to ca 1.0 for natural isotopic abundance ice. At HDice 1.0, alpha G is 1.7. Values of alpha G were obtained for 99.8 D2O over a temperature range of 4.2 to 196 K. The separation factor was found to be inversely proportional to temperature. The results of this study are compared with those in a previously published EPR study of stabilized H and D atoms after irradiation at 4.2 K. The observed effects are discussed briefly in terms of several models of selective energy absorption. Author
- Atomic and Molecular Physics and Spectroscopy