Baev Alexander, Salek Pawel, Gel'mukhanov Faris, Agren Hans
Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, New York 14260-3000, USA.
J Phys Chem B. 2006 Mar 23;110(11):5379-85. doi: 10.1021/jp0566663.
In the present work we outline the implications of a quantum-classical approach for modeling two-photon absorption of organic chromophores in solution. The approach joins many-photon absorption dynamic simulations with quantum chemical first principles calculations of corresponding excitation energies and transition matrix elements. Among a number of conclusions of the study, we highlight three: (i) The use of either short- or long-pulse excitation is demonstrated to switch the absorptive capacity of the nonlinear medium owing to enhancement of the nonlinear stepwise processes; (ii) The two-photon cross section strongly depends on the way in which the dephasing rate decays when the laser frequency is tuned off-resonant with the corresponding molecular transition; (iii) The results of the pulse propagation simulations based on electronic structure data obtained with a new Coulomb attenuated functional is shown to be in much better agreement with the experimental results than those based on data received with traditional density functionals.
在本工作中，我们概述了一种量子-经典方法对溶液中有机发色团双光子吸收进行建模的意义。该方法将多光子吸收动力学模拟与相应激发能和跃迁矩阵元的量子化学第一性原理计算相结合。在该研究的众多结论中，我们突出三点：（i）由于非线性逐步过程的增强，证明使用短脉冲或长脉冲激发可切换非线性介质的吸收能力；（ii）当激光频率调至与相应分子跃迁失谐时，双光子截面强烈依赖于退相速率的衰减方式；（iii）基于用新的库仑衰减泛函获得的电子结构数据进行的脉冲传播模拟结果，与基于传统密度泛函获得的数据相比，显示出与实验结果的一致性要好得多。
