不同能量的H3+、H2+、H+離子束撞擊H2O及D2O冰晶之光譜分析

The spectra analysis of H3+、H2+、H+ ion-bombarded on H2O、D2O ices in different ion energy

蔡銘聰(Ming-tsumg Tasi)

指導教授 ： 李雄

國立中央大學/工學院/機械工程學系/碩士(2007年)

摘要

我們的行星系統，是由星際間密集分子雲(dense molecular cloud)崩潰之後所形成的，而星際間密集分子雲是由氣體和微小晶粒(sub-micrometre sized grain)所組成。在太空低溫的環境中氣體會凝結在這些微小晶粒上形成薄冰，冰的主要成份為H2O，故我們選擇以H2O冰來做主要的研究。本實驗也觀察了D2O冰晶之光譜並且可以了解同位素對光譜的影響。
本實驗運用超高真空與低溫技術建立一個低溫(28K)、低壓(3*10-9 Torr)來模擬外太空的環境，配合薄膜生長技術長出冰晶，使用不同的入射離子(H+、H2+、H3+)模擬太陽風中具有能量的帶電粒子撞擊H2O冰晶，觀察冰晶經過撞擊後在300nm~500nm的可見光範圍所產生的光輻射訊號。最後經由光譜分析討論可以得知帶電粒子對於冰晶的演化過程所造成的影響。
我們將實驗所得的光譜做Gaussian Fitting分析，結果發現以H+、H2+、H3+撞擊H2O及D2O冰晶會產生OH譜線( 310nm、437nm )、H2O譜線( 380nm、420nm )、H2譜線( 465nm )及H-Balmer原子光譜( 433nm、485nm )。
而以相同能量之離子束( H3+、H2+、H+ )撞擊H2O冰或D2O冰所產生的光強度比較中，其強弱順序為：H3+>H2+>H+。
此外，由實驗結果我們也確定了同位素效應造成D2O冰晶之光譜光強度會大於H2O冰晶之光譜光強度。

關鍵字

離子束 ； 光譜分析

並列摘要

Our planetary system is composed of the collapse of dense molecular cloud, and the dense molecular cloud is composed of gases and sub-micrometer sized grains. In the low-temperature environment in the outer space, gases form into ice on the grains. Therefore, we choose H2O as our research material. In addition, we studied the spectrum of D2O ice and were able to understand the difference in spectrums of isotopes.
We applied the techniques of super-high vacuum and low temperature. In a low-temperature environment (28K) and low-pressure (3*10-9 Torr) environment, we made the ice grow using the thin film technique. Then we used different incident ions (H+、H2+、H3+) to simulate the energetic charged particles in the solar wind. Finally we studied the signals emitted during the collision in the range 300nm~500nm of visible light. In doing so, we are able to see the effect of charged particles to the evolution of the ice.
Using Gaussian fitting to analyze the spectrums we got, we found that by hitting H2O and D2O ice with H+、H2+、H3+ we got OH( 310nm、437nm )、H2O( 380nm、420nm )、H2( 465nm ) and H-Balmer( 433nm、485nm )。
Moreover, with the same incident energy of different ions H3+、H2+、H+, we can find the intensity of signals in sequence: H3+>H2+>H+.
Furthermore, from the results we could ascertain the effect that the intensity of signals from D2O ice is higher than that from H2O.

並列關鍵字

spectra analysis ； ion beam

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