Author/Authors :
Takeshi and Iketaki، نويسنده , , Yoshinori and Watanabe، نويسنده , , Takeshi and Ishiuchi، نويسنده , , Shun-ichi and Sakai، نويسنده , , Makoto and Omatsu، نويسنده , , Takashige and Yamamoto، نويسنده , , Kimihisa and Fujii، نويسنده , , Masaaki and Watanabe، نويسنده , , Tsutomu، نويسنده ,
Abstract :
By using a two-color dip spectroscopy, we measured the fluorescence intensity from tryptophan in a water solution. The fluorescence intensity exponentially decreased as the laser intensity for the Sn←S1 excitation increased. The phenomenon was analyzed by a rate-equation for a three-state model. The analysis shows that tryptophan with the Sn state has a radiationless relaxation process without any process through the S1 state, and that the Sn→S1 internal conversion does not have a 100% yield. The branching ratio of the process is estimated to be 20%. The presented result clarifies in detail the real meaning of Kasha’s rule.
