Dynamics of internal rotation related to the intramolecular charge-t transfer reactions

本项目的目的是确定能够形成分子内电荷转移（CT）态的化合物的内旋转势，然后观察扭转反应坐标上CT态形成的动力学。以下主题已被广泛研究1。测定了9，9 ′-联蒽基（BA）-稀有气体配合物和BA-Ar配合物的内转动势能面。在He络合物中，小扰动使简并扭曲能级轻微分裂，而在Ar和O络合物中，势的形状发生了剧烈变化，双阱势中的一个阱消失. BA络合物的时间分辨荧光BA-Ar络合物只发射激发态S_1的荧光，而BA-H_2 O络合物同时发射激发态S_1和CT的荧光。BA-Ar荧光的时间分布被发现是独立的 ...更多信息 波长，这可能表明在检测系统的时间分辨率内的快速IVR。BA-H_2 O络合物的时间曲线具有波长依赖性，在375 nm激发波长下，络合物的衰减速率为10 ps，而在380 nm激发波长下，络合物的衰减速率为20 ps。CT荧光随20 ps上升时间增加。这种行为表明中间状态的存在，这可能是指振动热CT状态3。用时间分辨荧光耗尽（TRFD）方法观察了BA-Ar和BA-H_2 O络合物激发态的快速退相过程。在BA-Ar复合物中，观察到的10 ps退相时间对应于分子内振动能的重新分布，而在BA-H_2 O复合物中，观察到的6 ps退相时间可以归因于IVR和CT态的形成.动力学过程的模拟用ps激发制备的波函数随时间的演化模拟了BA-H_2 O复合物中IVR和CT态的同时形成。观察到的行为得到了很好的再现。少

The aim of this project is to determine the internal rotation potentials of the compounds capable of forming an intramolecular charge-transfer (CT) state and then to observe the dynamics of the CT state formation on the twisting reaction coordinate. The following topics have been extensively studied1. Determination of the potential energy surface of internal rotationThe potential energy surfaces for the internal rotation of 9,9'-bianthryl (BA) -rare gas and BA-Ar complexes were determined. In a He complex the small perturbation slightly splits the degenerate twisting levels whereas in Ar and O complexes the shape of the potential is drastically changed ; one well of the double well potential disappears.2. The time-resolved fluorescence of BA complexesThe BA-Ar complex only emits the fluorescence from the excited S_1 state whereas the BA-H_2 O complex gives the fluorescence from both the S_1 and the CT states. The time profile of the BA-Ar fluorescence was found to be independent of the … More wavelength observed, which probably indicated the rapid IVR within the time resolution of the detecting system. On the other hand, the time profile of the BA-H_2O complex showed the wavelength dependence ; at the excitation wavelength 375 nm), it decayd very rapidly within 10 ps whereas at 380nm it increased first and then decreased with the time constant of 20 ps. The CT fluorescence increased with 20 ps rise time. This behavior indicates the presence of the intermediate state which probably be assignable to the vibarationally hot CT state3. The observation of the relaxation processes with the time-resolved fluorescence depletion (TRFD) methodWith the TRFD method, the rapid dephasing processes of the excited state of BA-Ar and BA-H_2O complexes have been observed. In the BA-Ar complexes, the observed dephasing of 10 ps corresponded to the intramolecular vibrational energy redistribution whereas in BA-H_2O complexes the observed 6 ps dephasing time could be attributed to both the IVR and CT state formation.4. A simulation of the dynamic processesThe simultaneously occurring IVR and CT state formation in the BA-H2O complexes was simulated in terms of the time-evolution of the wavefunction prepared by the ps excitation. The observed behavior was well reproduced. Less