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酞菁锌分子激发态的超快内转换和振动弛豫
Ultrafast Investigation of the Internal Conversion and Vibrational Relaxation in Excited States of Zinc Phthalocyanine Derivatives*
【摘要】 用飞秒时间分辨荧光亏蚀法研究了四特丁基酞菁(BuPc)、四特丁基酞菁锌(ZnBuPc)和四丙氧基酞菁锌(ZnPrPc)激发态的超快驰豫过程。用波长为398mm和796mm的超短脉冲激光激发分子,观察了S2态到S1态的内转换,其特征时间约为30fs。在796mm先于398mm作用于样品分子时,观察到了荧光强度渐变的过程,通过分析认为这一过程反映了S1的振动驰豫。通过对实验数据的拟合,得到了它们的振动驰豫特征时间,BuPc分子为1.5ps,ZnBuPc和ZnBuPc的特征时间分别为13.4和7.6ps。
【Abstract】 An internal conversion(IC)process from the S2 state to the S1 state of tetratertbutylphthalocyanine(BuPc),Zinc tetratertbutylphthalocyanine(ZnBuPc)and Zinc tetratpropoxyphthalocyanine(ZnPrPc)has been investigated respectively using femtosecond timeresolved fluorescence depletion methodThe S2 state of BuPc,ZnBuPc and ZnPrPc was prepared by the excitation of a 398nm laser pulse of 100fs durationVia a fast IC process from S2 to S1,the excited molecule emitted fluorescence from the S1 stateHowever,an ultrafast 796nm laser pulse depopulated the S2 state and therefore weakened the fluorescenceThe time scale of IC is estimated to be tens of femtosecondsThe vibrational relaxation in the S1 state was also studied by two 796nm photon excitation followed with a 398nm dumping laser pulseThe decay rate was measured as 15ps for BuPcFor ZnBuPc and ZnPrPc,decay rate of 134ps and 76ps were also observed respectively
【Key words】 Femtosecond time resolution Fluorescence depletion Zinc phthalocyanine Internal conversion Vibrational relaxation;
- 【文献出处】 化学物理学报 ,CHINESE JOURNAL OF CHEMICAL PHYSICS , 编辑部邮箱 ,1998年01期
- 【分类号】O561.4
- 【被引频次】42
- 【下载频次】146