时间域方法分析镍卟啉的共振拉曼强度与S2激发态结构

研究了入射光波长与S0→S2跃迁共振的情形下，卟啉镍配合物（NiP）的振动拉曼光谱。用时间域方法计算了NiP的共振拉曼强度和吸收光谱。结果表明，相对于基态，S2态NiP的分子构型沿着ν8和ν2简正坐标有较大的位移。这些简正坐标主要涉及卟啉环的CαCm键和CβCβ键伸缩运动，以及CαCmCα变角运动。与基态相比， S2态的CβCβ、 CαCm和CαN键分别增大0.27、 0.14、 0.07 pm，而CαCβ键则减小0.20 pm，与前人的赝势分子轨道计算（SPMO）结果相近。还从RR强度角度讨论了S2态的Jahn-Teller畸变。

Resonance Raman Intensities and Structure of S2 State of Nickel(II) Porphyrin by Time-Dependent Approach

Resonance Raman intensities and UV-visible absorption spectrum of nickel(II) porphyrin (NiP) were analyzed with time-dependent formulas under standard approximations for Condon mechanism of enhancement. The resultant dimensionless displacements on S2 state are comparable with those obtained by Spiro et al. from Kramers-Kronig transform methods. It was deduced from the calculations that there are large dimensionless displacements on the excited state along ν8 and ν2 coordinates. These normal modes consist of relatively large components of CβCβ, Cα Cm bond stretching and CαCmCα bond bending motions. Compared with the ground state, the average bond-lengths of　CβCβ, CαCm, and CαN bonds at S2 state increase respectively by 0.27, 0.14, and 0.07pm，while that of CαCβ bond decreases by 0.20pm，which are well in coincident with the SPMO calculations in literature.