我們量測了兩個晶體結構相同的三五族半導體材料 GaAs 與 InP 的反射與 穿透頻譜，並推得吸收係數頻譜，並且將吸收係數頻譜與雙聲子聯合能態密度 做比對，列舉了觀察到的與聯合能態密度有關聯性的特徵頻率位置，這些觀察 到的特徵頻率位置都與以往的文獻有許多一致的地方。
針對這些特徵頻率，做附近的能態密度奇異點分析，標註出吸收係數頻 譜特徵主要貢獻的聲子組合以及臨界點位置。
另外我們將奇異點與雙聲子支組合的臨界點分析由對稱點、對稱線以及 第一布里淵區中的單一對稱面拓展到不可約布里淵區 IBZ 所包含的所有對稱點、
軸、面以及內部空間。
在我們的分析結果中，除了有位於對稱性高的對稱點與對稱線上的臨界 點以外，發現了在 IBZ 另外三個對稱面上的其他臨界點。
而 GaAs 與 InP 兩種材料除了吸收係數頻譜的特徵明顯與否不同之外，因 為單位晶格構成原子的質量差距大小不同，有著不同類型的聲子色散關係、能 態密度頻譜，也讓這兩個材料的臨界點在動量空間中有不同的分布，GaAs 的臨 界點主要位於個對稱線與對稱點上，IBZ 的對稱面上分布比較少，InP 則是有較 多來自 IBZ 對稱面上的臨界點分布。
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