Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, SP.
J Phys Chem A. 2010 Mar 18;114(10):3466-70. doi: 10.1021/jp910010g.
In this work we investigate the degenerate two-photon absorption spectrum of all-trans retinal in ethanol employing the Z-scan technique with femtosecond pulses. The two-photon absorption (2PA) spectrum presents a monotonous increase as the excitation wavelength approaches the one-photon absorption band and a peak at 790 nm. We attribute the 2PA band to the mixing of states (1)B(u)(+)-like and |S(1)>, which are strongly allowed by one- and two-photon, respectively. We modeled the 2PA spectrum by using the sum-over-states approach and obtained spectroscopic parameters of the electronic transitions to |S(1)>, |S(2)> ("(1)B(u)(+)"), |S(3)>, and |S(4)> singlet-excited states. The results were compared with theoretical predictions of one- and two-photon transition calculations using the response functions formalism within the density functional theory framework with the aid of the CAM-B3LYP functional.
在这项工作中，我们采用飞秒脉冲的 Z 扫描技术研究了全反式视黄醛在乙醇中的简并双光子吸收光谱。双光子吸收（2PA）光谱随着激发波长接近单光子吸收带单调增加，并在 790nm 处出现峰值。我们将 2PA 带归因于态（1）B(u)(+) 类似态和 |S(1)>之间的混合，它们分别通过单光子和双光子强烈允许。我们通过使用态和求和方法来模拟 2PA 光谱，并获得了电子跃迁到 |S(1)>、|S(2)>（“(1)B(u)(+)”）、|S(3)>和 |S(4)>单激发态的光谱参数。结果与使用响应函数形式的单光子和双光子跃迁计算的理论预测进行了比较，该理论预测是在密度泛函理论框架内使用 CAM-B3LYP 函数完成的。
