Discovery of the radical cations of van der Waals complexes and their stepwise photoinduced reactions

随着自由喷流膨胀和多光子电离技术的出现，气相中货车范德华（vdW）配合物分子离子的研究得到了发展。然而，在凝聚相中，相应的研究很少。本研究项目首次发现了vdW分子在刚性溶液中的自由基阳离子，并研究了它们的分步光诱导反应。特别地，苯-乙烯在氟里昂基质中的系统被广泛地研究，发现电离的二元复合物在约1- 2 eV处表现出强的电荷转移带。电离体系的光激发导致了辛四烯的价态异构化。结果表明，二元配合物的电离大大提高了化学反应活性。随着乙烯浓度的增加，还发现了C_ H_2组成的另一种产物<10><14>。本工作应被看作是随着短波长激光技术的发展而预期的气相研究的先导性研究。

Studies of molecular ions of van der waals (vdW) complexes in the gas phase are being developed with the advent of the free-jet expansion and the multiphoton ionization techniques. However, in condensed phase the corresponding study is scarce. In this research project some radical cations of vdW molecules in rigid solutions are newly found and their stepwise photoincduced reactions are studied. In particular, the system of benzene-ethylene in Freon matrices is studied extensively to find that the ionized binary complex exhibits a strong charge-transfer band at about 1-2eV. Photoexcitation of the ionized system leads to the valence isomerization to the radical cation of octatetraene. The result indicates that ionization of binary complexes enhances the chemical reactivity greatly. With the increase of the concentration of ethylene another product of the composition of C_<10>H_<14> is also found.The present work should be regarded as a pilot study for the future study in the gas phase which is anticipated with the development of short wavelength laser technology.