針對[Cr(CN)5NO]3-和[Cr(NH3)5NO]2+錯離子，採用密度泛函理論(Density Function Theory)之B3LYP方法計算它們的自旋基態性質。並以[Cr(CN)6]n-(n=3、4、5)與[Cr(NH3)6]m+(m=1、2、3)兩種相關的錯離子作為參考組，對[Cr(CN)5NO]3-和[Cr(NH3)5NO]2+錯離子進行振動頻率、原子淨電荷、電子自旋密度的比對。進一步研判出[Cr(CN)5NO]3-和[Cr(NH3)5NO]2+錯離子的中心鉻原子的特性。 將B3LYP計算的幾何優選結果配合單激發組態作用 (CI-Single)的方法計算[Cr(CN)5NO]3-和[Cr(NH3)5NO]2+錯離子有關錯離子NO部份的振動頻率與激發能量。計算的結果與UV-vis的光譜資料比對，研判錯離子[Cr(CN)5NO]3-和[Cr(NH3)5NO]2+的鉻原子可能的氧化狀態較接近Cr(Ⅱ)。 Abstract On the basis of density functional theory (DFT), the chromium-nitrosyl complexes [Cr(CN)5(NO)]3- (S=1/2) and [Cr(NH3)5NO]2+ (S=1/2) are studied via the B3LYP hybrid method. The vibration frequencies, atomic net charges, and spin densities of the complexes are analyzed. In order to determine the characteristics of the central chromium of the chromium-nitrosyl complexes, the related complexes [Cr(CN)6]n- ((n=3、4、5) and [Cr(NH3)6]m+ (m=1、2、3) are employed as reference compounds. By using the CI-Single method, the calculated excitation energies are in good agreement with the IR and UV-vis data. After compared with experimental spectroscopy data, the results indicate that the effective chromium oxidation states for both complex ions approach Cr(Ⅱ).
