Is the large molecular deformation in TICTphenomenon really twisting mode?

TICT现象最早是由E.Lipert等人于1962年发现的。K.Rotkiewicz等人于1973年进行了解释和命名。到目前为止，世界各地的许多科学家已经证实了它存在于许多由供体和受体发色体组成的芳香族分子中。它的概念一度似乎已经确立。然而，我们认为TICT现象中的大分子形变是否真的是扭曲模是值得怀疑的，尽管我们可以在解释中认识到大形变和电荷转移过程。在科学研究补助金(C)(2)的帮助下，核查调查已经进行了两年。利用超音速喷射激光光谱，我们观测到了一些具有代表性的TICT分子的S_0-S_1电子跃迁。通过对它们的详细分析，可以得出如下观点：S_1态和TICT态由于能量的接近而振荡性地相互作用。结果，我们在喷冷对氰基苯基吡咯的S_0-S_1电子跃迁中观察到了纠缠振动模，表明了电子态的混合。分析得出两个结论：1.在电子激发下，吡咯和苯甲腈平面之间的二面角从39度减小到20度。在394 cm^-1&gt；振动坐标方向上发生了较大的变形，模式的显式振动指定尚未完成并正在进行中。

TICT phenomenon was firstly observed by E. Lipert et al at 1962. The interpretation and nomenclature was carried out by K. Rotkiewicz et al at 1973. Many world-wide scientists have as far confirmed it in many aromatic molecules consisting of donor and acceptor chromophers. Its concept has once seemed to be established. We have, however, thought it doubtful whether the large molecular deformation in TICT phenomenon is really twisting mode, although we could have recognized 'large deformation and charge transfer process' in the interpretation. With help of the Grant-in-Aid for Scientific Research (C)(2), the check investigation has been carried out for two years. Using a supersonic-jet laser spectroscopy we observed the S_0-S_1 electronic transitions of some of representative TICT molecules. The detail analysis of them should lead to the elucidation on the basis of the following idea, the S_1 and TICT states vibronically and mutually interact because of their energetic proximity. As a result, we observed the tangle vibronic pattern, indicating the electronic-state mixing, in the S_0-S_1 electronic transitions of jet-cooled p-cyanophenylpyrrol. The analysis leads to two conclusions,1. Upon the electronic excitation, the dihedral angle between the pyrrol and benzonitrile planes decreases from 39 to 20 degrees.2. Large deformation occurs along the direction in the 394 cm^<-1> vibrational coordinate.The explicit vibronic assignment of the mode has not yet completed and in progress.