The reaction mechanism and kinetics of oxygen isotope exchange between tens of nanometer-sized amorphous silicate grains with forsterite composition (amorphous forsterite) and low-pressure carbon monoxide (CO) gas () of 0.05–1 Pa at 643–883 K were examined to investigate oxygen isotopic evolution in the protosolar disk that led to the mass-independent oxygen isotopic variation of planetary materials. Both CO gas supply- and diffusion-controlled isotope exchange reactions were observed. At 753–883 K and of 0.05–1 Pa, the supply of CO gas controls the isotope exchange reaction, and its rate is 2–3 orders of magnitude smaller than that of the HO supply-controlled isotope exchange reaction. The diffusion-controlled isotope exchange occurred at 643–703 K and of 0.3 Pa, and the reaction rate of (m/s) = (3.1 ± 2.3) × 10 exp[−41.7 ± 9.6 (kJ mol) (1/ − 1/1200)] was obtained.

中文翻译：

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早期太阳系中非晶硅酸盐尘埃与一氧化碳气体之间氧同位素交换反应的实验模拟


研究了数十个具有镁橄榄石成分的纳米级无定形硅酸盐颗粒（无定形镁橄榄石）与 643–883 K 下 0.05–1 Pa 的低压一氧化碳 (CO) 气体 () 之间氧同位素交换的反应机理和动力学，研究原太阳盘中的氧同位素演化，该演化导致了行星材料的与质量无关的氧同位素变化。观察到 CO 气体供应和扩散控制的同位素交换反应。在 753–883 K 和 0.05–1 Pa 条件下，CO 气体的供应控制同位素交换反应，其速率比 H2O 供应控制的同位素交换反应小 2–3 个数量级。扩散控制的同位素交换发生在 643–703 K、0.3 Pa，反应速率 (m/s) = (3.1 ± 2.3) × 10 exp[−41.7 ± 9.6 (kJ mol) (1/−1) /1200)]获得。