| 摘要: | 在銀河系中有許多星際冰晶，其主要由 H2O，NH3，CH3OH，CH4，CO，CO2等等分子所構成，在低溫（10K-100K）下這些分子會附著於星際間粒子或隕石上形成星際冰晶。同時宇宙中也存在著許多由恆星所發出的高能粒子(帶有一定能量)，如太陽系中的太陽風高能粒子。星際冰晶被這些高能粒子撞擊後，冰晶中分子的組成便會改變而產生有機物。這些隕石上產生的有機物會隨著隕石墜落於行星上，伴隨隕石而來的有機物會在行星生命演化上扮演重要的角色，特別是原本無有機物的行星。 在這篇論文裡，這些冰晶受高能粒子撞擊產生有機物質的反應機制，是我們主要探討的地方。實驗在低溫(24 K)高真空(6×10-10 torr)下模擬外空環境，並且用15keV的 H3+離子，撞擊含 CH 鍵或 CO 鍵的冰晶化合物。此冰晶化合物包括 CH4、 CO2，以各種比例和 H2O 混合做為實驗的控制變因。最後藉由傅式紅外光譜儀(FTIR)掃描冰晶轟擊前後的紅外光譜圖。分析在不同條件下，CO、 CO2以及 CH3OH 的生成情況 。 There are many interstellar ices in the galaxy, and its main composition includes H2O, NH3, CH3OH, CH4, CO, CO2, etc. Under the low temperature (10K -100K), these molecules tend to attach to the surfaces of the interstellar particles or the meteorites, and then become interstellar ice. Meanwhile, there are also many particles (with energy to some degree) that ejected by other stars in the universe, like the solar wind of the solar system. When bombarded with these energetic particles, the molecule structure of the interstellar ice could be changed and produce organic matters. Those interstellar ices on the surfaces of the meteorite, which had turned into organic matters, may fall on a planet with the meteorite, and bring the organic matters to that planet. This could make a significant change to the evolution of the planet, especially for the planet where the organic matters never exist before. The mechanism of the reaction that produces organic matter out of ice crystal is the main topic that we wanted to probe into in this essay. In our experiment, we utilized the cryogenic technique (24 K) and the ultra-high vacuum (6×10-10 torr) to simulate the environment of outer space. And we used H3+ ions (15keV) to bombard the chemical compounds (the ice crystal) with CH-bonds or CO-bonds. The chemical compounds, including CH4 and CO2, mixed with H2O in various proposition are the controlled variables in the experiment. Finally, we used FTIR to scan the ice crystal, both before and after the bombardment, and then analyze the quantity of the CO、 CO2 and CH3OH bonds produced under the different conditions. |
