Photochemistry of Lanthanide Ions-Multiphoton Chemistry via 4f Electronic Excited States-

在双色双光子逐步激发的激光照射下，酒精中的镱3+离子被还原为相应的2+离子。持续时间为4ns的975 nm红外脉冲将基态泵送到4f激发态，跃迁为2F5/2-2F7/2，第二个光子（355 nm）产生Cl3d到Yb4f的电荷转移态（CT）；然后发生还原。激光能量依赖于紫外和红外的每种颜色，以及红外波长证明了上述机制。利用纳秒激光光解测量了双光子化学从4f激发态（2F5/2）到CT态的中间吸收光谱。中间光谱出现在波长短于400nm的地方。单光子激发下的反应产率为0.1 ~ 0.2，双光子激发下第二光子的反应产率为0.1 ~ 0.2。这些化学物质有望用于核废料处理。

Ytterbium 3+ ions in alcohol were found to be reduced to the corresponding 2+ ions upon laser irradiation with a stepwise two-color two-photon excitation.The infrared (975-nm) pulse with a duration of 4 ns pumps the ground state to the 4f excited state with the transition of 2F5/2-2F7/2, and the second photon (355-nm) generates the charge transfer(CT)state of Cl3d to Yb4f;the reduction then occurs. Laser energy dependencies on each color of UV and IR, and on IR wavelengths demonstrate the above mechanism. The intermediate absorption spectrum in the two-photon chemistry was measured from the 4f excited state (2F5/2) to the CT state by nanosecond laser photolysis.The intermediate spectrum appears in the wavelengths shorter than 400 nm.The reaction yields for single- photon UV excitation and the second photon in the two-photon excitation were 0.1-0.2. These chemistries are hopefully useful for nclear waste treatment.