I2-环己烯复合物的共振拉曼光谱和密度泛函理论计算研究

实验得到I2-环己烯电荷转移复合物的电子吸收光谱和共振拉曼光谱.用密度泛函方法计算了复合物的基态结构、振动频率和电子跃迁能.计算和吸收光谱实验结果表明,I2-烯烃复合物在约300nm处的强吸收带为pz(I17)→π*(C=C)跃迁,即由靠近C=C双键端的碘原子(I17)上的一个pz电子向C=C双键反键轨道跃迁引起的吸收.在约300nm共振拉曼光谱的强度模式表现为I—I伸缩振动模和C=C伸缩振动模的基频、泛频及其组合频,表明在该激发态上I2-环己烯复合物经历了显著的I—I和C=C的价键变化.

Resonance Raman Spectroscopy and Density Functional Theory Calculation Investigation of I2-cyelohexene Complex

Resonance Raman spectra of I2-cyclohexene charge-transfer complex were obtained with three excitations at ～300 nm absorption band of the complex. Density functional theory calculations were carried out to examine the structure and normal mode frequencies of the ground state of the complex and its electronic transition energies. The strong absorption band around 300 nm was assigned to pz (I17)→ π*(C=C) transition,that is the transition of a pz electron from I atom at C=C terminal to anti-bonding orbital of C=C double bond. The resonance Raman spectra displayed the Raman intensity in the overtones and combination bands of the nominal I—I stretch and C=C stretch modes.This suggested that the complex underwent an obvious valence change in both I—I and C=C.