Atomic oxygen diffusion on and desorption from amorphous silicate surfaces.
Atomic oxygen diffusion on and desorption from amorphous silicate surfaces.
复制标题
原子氧在无定形硅酸盐表面上的扩散和解吸。
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
G. Vidali
中科院分区：
文献类型：
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作者：
Jiao He;Dapeng Jing;G. Vidali
涉及原子氧的表面反应在天体物理学和天体化学中引起了很大的关注，但两个最基本的表面过程，解吸和扩散，还没有得到很好的理解。我们研究了原子氧的扩散和解吸或从非晶硅酸盐表面在模拟星际条件下使用射频解离氧束。利用程序升温脱附（TPD）实验研究了沉积在硅酸盐表面的原子氧和分子氧反应生成臭氧的过程。研究发现，在40 K至50 K之间，原子氧开始显着扩散。采用速率方程模型研究了臭氧生成实验中的表面动力学。测得原子氧脱附能为152 ± 20 meV（1764 ± 232 K）。新发现的原子氧解吸能比公认的值高得多，这可能解释了观测和化学模型之间空间中分子氧丰度的差异。
Surface reactions involving atomic oxygen have attracted much attention in astrophysics and astrochemistry, but two of the most fundamental surface processes, desorption and diffusion, are not well understood. We studied diffusion and desorption of atomic oxygen on or from amorphous silicate surfaces under simulated interstellar conditions using a radio-frequency dissociated oxygen beam. Temperature programmed desorption (TPD) experiments were performed to study the formation of ozone from reaction of atomic and molecular oxygen deposited on the surface of a silicate. It is found that atomic oxygen begins to diffuse significantly between 40 K and 50 K. A rate equation model was used to study the surface kinetics involved in ozone formation experiments. The value of atomic oxygen desorption energy has been determined to be 152 ± 20 meV (1764 ± 232 K). The newly found atomic oxygen desorption energy, which is much higher than the well-accepted value, might explain the discrepancy in abundance of molecular oxygen in space between observations and chemical models.