Multiphoton reduction of lanthanide ions and isotope enrichment by a high intensity laser

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Eu^<3+>→Eu^<2+> ReductionEuropium 3+ ions in methanol were found to be reduced to the corresponding 2+ ions upon irradiation with intense femtosecond laser pulses. The excitation wavelength of 800 nm was nonresonant with their electronic transitions of Eu^<3+>. It is notable that femtosecond white-light laser was generated when the reactions occurred. The mechanisms can be explained in terms of solvated electron formation followed by the reduction. The electron ejection in a focused beam in solution has been known to be accompanied by white-light laser.Sm^<3+>→Sm^<2+> ReductionSamarium 3+ ions in methanol were found to be reduced to the corresponding 2+ ions upon irradiation with intense femtosecond laser pulses. The reduction was observed at both pulses with central wavelengths of 403 nm converted from an 800-fs fundamental pulse and 800 nm with a duration of 43 fs. When the laser wavelength was tuned to the 4f-4f absorption at 403 nm corresponding to the ^6P_<3/2>←^6H_<5/2> transitio … More n, the the reduction occurred by multiphoton absorption presumably due to reaching the deep charge transfer state. In the case of excitation by 800-nm pulses of the fundamental wavelength of the Ti:sapphire laser, the reduction is considered to occur via solvent ionization followed by electron capture by Sm^<3+>. The product Sm^<2+> was detected by its fluorescence, which was observed for the first time in solution and showed a broad spectrum peak around 750 nm with a quantum yield of 0.050 in methanol in the presence of 15C5-ether.Isotope EnrichmentThe molar extinction coefficient of the ^6P_<3/2>←^6H_<5/2> transition is reportedly 10% different between ^<144>Sm^<3+> and ^<154>Sm^<3+> in solution : therefore, different isotope distributions among Samarium 2+ ions should be realized after the multiphoton reduction from Sm^<3+> to Sm^<2+>. This confirmation is currently in progress.Preliminary results for Yb^<3+>→Yb^<2+> ReactionYb^<3+> has successfully reduced to Yb^<2+> by femtosecond pulse excitation with pulse duration of about 100 fs at three wavelengths of 800 nm, 970 nm, and 1930 nm. Yb^<3+> has the 4f-4f transition at 970 nm ; however, resonance enhancement for the formation of Yb^<2+> was not clear at this stage. Less