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

随着自由射流膨胀和多光子电离技术的出现，对气相范德华络合物分子离子的研究得到了发展。然而，在凝聚态方面的相关研究却很少。本课题在刚性溶液中新发现了一些vdW分子的自由基阳离子，并对它们的逐步光诱导反应进行了研究。特别是，对氟利昂基体中苯-乙烯体系进行了广泛的研究，发现电离的二元配合物在约1-2eV处表现出很强的电荷转移带。电离体系的光激发导致价异构化成八四烯的自由基阳离子。结果表明，二元配合物的电离作用大大提高了化学反应性。随着乙烯浓度的增加，还发现了C_<10>H_<14>的产物。随着短波激光技术的发展，本研究可作为未来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.