Department of Physics and Astronomy, The Open University, Milton Keynes, MK7 6AA, UK.
Phys Chem Chem Phys. 2011 Jan 14;13(2):421-7. doi: 10.1039/c0cp00448k. Epub 2010 Nov 15.
The formation of six ozone isotopomers and isotopologues, (16)O(16)O(16)O, (18)O(18)O(18)O, (16)O(16)O(18)O, (18)O(18)O(16)O, (16)O(18)O(16)O, and (18)O(16)O(18)O, has been studied in electron-irradiated solid oxygen (16)O(2) and (18)O(2) (1 ∶ 1) ices at 11 K. Significant isotope effects were found to exist which involved enrichment of (18)O-bearing ozone molecules. The heavy (18)O(18)O(18)O species is formed with a factor of about six higher than the corresponding (16)O(16)O(16)O isotopologue. Likewise, the heavy (18)O(18)O(16)O species is formed with abundances of a factor of three higher than the lighter (16)O(16)O(18)O counterpart. No isotope effect was observed in the production of (16)O(18)O(16)O versus(18)O(16)O(18)O. Such studies on the formation of distinct ozone isotopomers and isotopologues involving non-thermal, non-equilibrium chemistry by irradiation of oxygen ices with high energy electrons, as present in the magnetosphere of the giant planets Jupiter and Saturn, may suggest that similar mechanisms may contribute to the (18)O enrichment on the icy satellites of Jupiter and Saturn such as Ganymede, Rhea, and Dione. In such a Solar System environment, energetic particles from the magnetospheres of the giant planets may induce non-equilibrium reactions of suprathermal and/or electronically excited atoms under conditions, which are quite distinct from isotopic enrichments found in classical, thermal gas phase reactions.
已在 11 K 下研究了电子辐照固体氧气 (16)O(2) 和 (18)O(2)（1∶1）冰中形成的六种臭氧同量异位素和同量异位物，(16)O(16)O(16)O、(18)O(18)O(18)O、(16)O(16)O(18)O、(18)O(18)O(16)O、(16)O(18)O(16)O 和 (18)O(16)O(18)O。发现存在明显的同位素效应，涉及富氧臭氧分子的富集。重同位素 (18)O(18)O(18)O 物种的形成比相应的 (16)O(16)O(16)O 同量异位物高约六倍。同样，重同位素 (18)O(18)O(16)O 物种的形成丰度比较轻的 (16)O(16)O(18)O 对应物高约三倍。在形成 (16)O(18)O(16)O 与 (18)O(16)O(18)O 时，没有观察到同位素效应。在巨行星木星和土星的磁层中存在的高能电子辐照氧气冰形成非热、非平衡化学的不同臭氧同量异位素和同量异位物的研究表明，类似的机制可能有助于木星和土星的冰卫星如木卫三、木卫四和土卫二上的 (18)O 富集。在这样的太阳系环境中，来自巨行星磁层的高能粒子可能会在与经典、热气相反应中发现的同位素富集条件截然不同的条件下，诱导超热和/或电子激发原子的非平衡反应。
