Department of Chemistry and State Key Laboratory of ATMMT(MOE), Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 May;75(5):1381-7. doi: 10.1016/j.saa.2009.10.054. Epub 2009 Nov 6.
Resonance Raman spectra of free-base tetraphenylporphine (TPP) were obtained with 397.9, 416, and 435.7nm excitation wavelengths and density functional calculations were done to elucidate the electronic transitions and the resonance Raman spectra (RRs) of TPP. The RRs indicate that the Franck-Condon region photodynamics for S(0)-->S(4) electronic state is predominantly along the C(m)-ph stretch while that for S(0)-->S(3) electronic state is predominantly along the porphin ring C(beta)C(beta) stretch. Non-totally symmetric vibrational modes were regularly presented in resonance Raman spectra: the shorter the excitation wavelengths were, the stronger intensity the modes had, which can be interpreted in terms of electric dipole transition moments caused by Franck-Condon and Herzberg-Teller coupling. Four non-total symmetry vibrational mode upsilon(52,)upsilon(64), upsilon(97) and upsilon(130) in A(2) irreducible representative of TPP were observed in 397.9, 416 and 435.7nm resonance Raman spectrum. With the shorter wavelength laser excitations at 416 or 397.9nm, the A(2) vibrational modes show more enhanced Raman intensity by comparison with those in the TPP spectrum excited at 435.7nm.
自由碱四苯基卟啉（TPP）的共振拉曼光谱分别在 397.9nm、416nm 和 435.7nm 激发波长下获得，并进行了密度泛函计算以阐明 TPP 的电子跃迁和共振拉曼光谱（RRs）。RRs 表明，S(0)→S(4)电子态的 Franck-Condon 区域光动力主要沿着 C(m)-ph 伸展，而 S(0)→S(3)电子态的光动力主要沿着卟啉环 C(beta)C(beta)伸展。非完全对称振动模式在共振拉曼光谱中经常出现：激发波长越短，模式的强度越强，可以用 Franck-Condon 和 Herzberg-Teller 耦合引起的电偶极跃迁矩来解释。在 TPP 的 A(2)不可约表示中，观察到四个非全对称振动模式 upsilon(52,)、upsilon(64)、upsilon(97)和 upsilon(130)在 397.9nm、416nm 和 435.7nm 共振拉曼光谱中。在 416nm 或 397.9nm 的较短波长激光激发下，与在 435.7nm 激发的 TPP 光谱相比，A(2)振动模式显示出更强的拉曼强度。
