화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.103, No.20, 3910-3916, 1999
Multiphoton reduction of Eu3+ to Eu2+ in methanol using intense, short pulses from a Ti : Sapphire laser
Multiphoton reduction of Eu3+ to Eu2+ in methanol was induced by irradiation with the second harmonic (394 nm, 2 ps) of a Ti:sapphire laser. The conversion efficiencies were increased to 0.3 for short pulse excitation, as compared to on the order of 10(-5) for a nanosecond dye laser pulse. It appears that a three-photon process pumps a deep charge-transfer state from which Eu3+ efficiently dissociates to Eu2+. On the basis of the excitation spectra, the first intermediate state is the L-5(6) state, which is one of the f-electronic excited states. The Eu2+ concentration increased shot by shot and approached a plateau. The saturation behavior will be explained in terms of the back photooxidation of Eu2+ to Eu3+.