由於一加速離子射束與固體表面碰撞時產生的受激粒子，會經由非輻射降激 (radiationless deexcitation) 或輻射降激釋放出光子的方式回到穩定態，以9keV, 6keV, 3keV的Ar+離子束及N2+離子束轟擊乾淨GaAs(100)表面時，我們可探討入射離子能量及種類與GaＩ三條原子光譜線GaＩ417.2nm, GaＩ403.3nm, GaＩ294.4nm輻射強度的關係；另外研究報告指出，不論是輻射降激或非輻射降激過程都與表面的化學狀態有很密切的關係，例如有氧氣分子的存在會增強鋁靶在離子轟打下光輻射的強度，實驗中分別以9keV Ar+離子束及9keV N2+離子束轟擊GaAs(100)表面，觀察GaＩ的三條原子光譜線輻射強度在腔體含有不同壓力的氧氣或氮氣下的變化，並計算氧的附著率及氧的濺射率。 The interaction of energetic ions with solid surfaces results in the emission of excited ions. The excited particles decay either by a radiationless deexcitation process or by radiative photon emission. In this study, we use 9keV, 6keV and 3keV Ar+ ions and N2+ ions bombard clean GaAs(100) target separately. Results of the measurements on the projectile energy and ion type dependences of Ga I 417.2nm, 403.3nm and 294.4nm lines are presented. It is known that the process of radiationless and radiative deexcitation are highly sensitive to the chemical state of the surface. For example, the presence of oxygen has been found to enhance the light emission from aluminium target under ion impact. In this study, we use 9keV Ar+ ions and N2+ ions bombard GaAs(100) to measure the light intensities are as a function of O2 or N2 pressure. Also, the oxygen sputtering coefficient So and oxygen sticking probability Cs are studied.